Video Generation (Seedance 2.0)

Pomex provides an asynchronous video generation API powered by Seedance 2.0. The workflow follows a task-based pattern: submit a generation request, then poll for results or receive a webhook callback when the video is ready.

Asynchronous API — Video generation takes time. The Create endpoint returns immediately with a task object. In the common case the initial status is queued; if upstream already returns a richer snapshot, Pomex will persist and return that status instead. Poll the Get endpoint or provide a callback_url to be notified on completion.

Overview

Endpoint Method Description
/v1/video/generations POST Create a new video generation task
/v1/video/generations GET List your video generation tasks
/v1/video/generations/{task_id} GET Get a specific task (poll for status/result)
/v1/video/generations/{task_id} DELETE Delete (cancel) a video generation task
/v1/video/assets POST Create (upload) a new media asset for use as reference
/v1/video/assets/{asset_id} GET Get asset status and details

Available Models

Model ID Description Capabilities
byteplus/seedance-2.0 Seedance 2.0 — BytePlus's state-of-the-art video generation model Text-to-video, Image-to-video, Video-to-video, Audio-driven

Task Status Lifecycle

Status Description Terminal?
queued Task accepted, waiting for GPU resources No
running Video is being generated No
succeeded Generation complete — video URL available in content Yes
failed Generation failed — see error field for details Yes
cancelled Task was cancelled via DELETE Yes

Create Video Generation

POST /v1/video/generations

Submit a video generation task. The response returns immediately with a task object containing a unique id for polling.

Request Body Parameters

Parameter Type Required Description
model string Yes Model identifier. Currently: "byteplus/seedance-2.0"
content array Yes Array of content items describing the video to generate (text prompts, reference images/videos/audio). Must contain at least 1 item.
duration integer No Video duration in seconds. Minimum 4 seconds. Maximum depends on the generation mode and upstream configuration. Forwarded as-is when present.
ratio string No Aspect ratio. Supported values: "16:9", "9:16", "1:1". Forwarded to upstream after trimming whitespace.
resolution string No Output resolution. Supported values: "720p", "1080p". Higher resolutions (e.g. "4k") are not supported by the current model and will be rejected by upstream.
seed integer No Optional upstream seed value. Pomex stores nothing special here; it is passed through when present.
framespersecond integer No Optional FPS hint forwarded as-is to upstream. Note the JSON field name is exactly framespersecond.
generate_audio boolean No Optional upstream flag for generating audio. If omitted, Pomex does not inject a default; upstream behavior applies.
draft boolean No Draft mode flag (faster generation with lower quality). Only supported in image-to-video (i2v) mode. Not supported in text-to-video (t2v) — sending draft in t2v mode will be rejected by upstream.
service_tier string No Optional upstream service tier string, forwarded after trimming whitespace.
callback_url string No Customer webhook target stored by Pomex. When the task reaches a terminal state and the URL is HTTPS, Pomex POSTs the task JSON to this URL. This value is platform-only and is not forwarded upstream as-is.
execution_expires_after integer No Requested execution timeout in seconds. If omitted, Pomex computes the effective timeout from provider config or falls back to 172800 seconds (48 hours).
metadata object No Arbitrary JSON metadata attached to the task. Returned in all subsequent responses.

Request Normalization Rules

Pomex does not reject every unsupported field combination. During create, it builds a sanitized upstream request body and drops unsupported fields or invalid content-item subfields where possible. A request is rejected only when required top-level fields are missing, or when sanitization leaves no valid content items.

Rule Behavior
Unsupported top-level fields Ignored for upstream submission. Example: custom fields such as watermark are dropped rather than forwarded.
text content role role is not forwarded on type="text" items.
Media item role Only the matching role is kept: reference_image for image_url, reference_video for video_url, reference_audio for audio_url. Other roles are dropped.
Wrong media field on item Extra fields such as text on a media item, or image_url on a video_url item, are dropped.
Invalid content items Items with unsupported type, missing required text, or missing required media URL are dropped. If all items are dropped, create returns 400.
callback_url The customer callback URL is stored by Pomex. If VIDEO_WEBHOOK_BASE_URL is configured, Pomex separately registers its own official upstream webhook endpoint at /v1/video/result.

Content Item Structure

Each element in the content array describes an input modality:

Field Type Description
type string Required. One of: "text", "image_url", "video_url", "audio_url"
role string Role for media items. Options: "reference_image", "reference_video", "reference_audio"
text string Text content (required when type is "text"). This is your generation prompt.
image_url object Image reference (required when type is "image_url"). Contains {"url": "..."}
video_url object Video reference (required when type is "video_url"). Contains {"url": "..."}
audio_url object Audio reference (required when type is "audio_url"). Contains {"url": "..."}

Generation Modes

These are common request shapes supported by the current request sanitizer and upstream mapping:

Mode Content Configuration Description
Text-to-Video [{type:"text", text:"..."}] Generate video from a text prompt alone.
Image-to-Video [{type:"text", text:"..."}, {type:"image_url", role:"reference_image", image_url:{url:"..."}}] Animate a reference image with a text prompt. The media role is optional but only reference_image is preserved if provided.
Video-to-Video [{type:"text", text:"..."}, {type:"video_url", role:"reference_video", video_url:{url:"..."}}] Transform or extend a reference video. Only reference_video is preserved if a role is provided.
Audio-driven [{type:"text", text:"..."}, {type:"image_url", role:"reference_image", ...}, {type:"audio_url", role:"reference_audio", audio_url:{url:"..."}}] Generate video synchronized to reference audio. Audio cannot be the only reference input — you must also include a reference_image or reference_video alongside the audio reference.

Parameter Constraints

Constraint Details
duration Minimum 4 seconds. Maximum depends on generation mode (typically 5–10s for i2v, up to 15s for t2v).
ratio Supported: "16:9", "9:16", "1:1".
resolution Supported: "720p", "1080p". Higher resolutions (e.g. "4k") are not supported.
draft Only supported in image-to-video (i2v) mode. Sending draft in text-to-video (t2v) will be rejected.
reference_audio Cannot be the only reference input. Must be combined with reference_image or reference_video.

Example: Text-to-Video

curl https://api.pomex.ai/v1/video/generations \
  -H "Authorization: Bearer $POMEX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "byteplus/seedance-2.0",
    "content": [
      {
        "type": "text",
        "text": "A golden retriever running through a field of sunflowers at sunset, cinematic 4K, slow motion"
      }
    ],
    "duration": 10,
    "ratio": "16:9",
    "resolution": "1080p"
  }'
import requests

resp = requests.post(
    "https://api.pomex.ai/v1/video/generations",
    headers={
        "Authorization": "Bearer YOUR_API_KEY",
        "Content-Type": "application/json",
    },
    json={
        "model": "byteplus/seedance-2.0",
        "content": [
            {
                "type": "text",
                "text": "A golden retriever running through a field of sunflowers at sunset, cinematic 4K, slow motion"
            }
        ],
        "duration": 10,
        "ratio": "16:9",
        "resolution": "1080p",
    },
)

task = resp.json()
print(task["id"], task["status"])
# → "task_abc123..." "queued"

Response (200 OK)

{
  "id": "task_01JXN4KQWER5678ABCDEFGH",
  "object": "video.generation.task",
  "created": 1748160000,
  "model": "byteplus/seedance-2.0",
  "status": "queued",
  "metadata": null
}

Example: Image-to-Video

curl https://api.pomex.ai/v1/video/generations \
  -H "Authorization: Bearer $POMEX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "byteplus/seedance-2.0",
    "content": [
      {
        "type": "text",
        "text": "The character slowly turns their head and smiles at the camera"
      },
      {
        "type": "image_url",
        "role": "reference_image",
        "image_url": {
          "url": "https://example.com/portrait.jpg"
        }
      }
    ],
    "duration": 5,
    "ratio": "9:16",
    "resolution": "1080p"
  }'

Example: With Audio and Callback

curl https://api.pomex.ai/v1/video/generations \
  -H "Authorization: Bearer $POMEX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "byteplus/seedance-2.0",
    "content": [
      {
        "type": "text",
        "text": "A musician playing piano in a dimly lit jazz club"
      },
      {
        "type": "image_url",
        "role": "reference_image",
        "image_url": {
          "url": "https://example.com/pianist-photo.jpg"
        }
      },
      {
        "type": "audio_url",
        "role": "reference_audio",
        "audio_url": {
          "url": "https://example.com/jazz-piano.mp3"
        }
      }
    ],
    "generate_audio": true,
    "duration": 15,
    "ratio": "16:9",
    "callback_url": "https://myapp.example.com/webhooks/video-done",
    "metadata": {"project": "music-video", "scene": 3}
  }'

Get Video Generation

GET /v1/video/generations/{task_id}

Retrieve the current status and result of a video generation task. If the task is still non-terminal, Pomex synchronizes the latest upstream snapshot before returning. Poll this endpoint until status reaches a terminal state (succeeded, failed, or cancelled).

Path Parameters

Parameter Type Description
task_id string The unique task identifier returned by the Create endpoint.

Example Request

curl https://api.pomex.ai/v1/video/generations/task_01JXN4KQWER5678ABCDEFGH \
  -H "Authorization: Bearer $POMEX_API_KEY"
import time
import requests

task_id = "task_01JXN4KQWER5678ABCDEFGH"
headers = {"Authorization": "Bearer YOUR_API_KEY"}

# Polling loop
while True:
    resp = requests.get(
        f"https://api.pomex.ai/v1/video/generations/{task_id}",
        headers=headers,
    )
    task = resp.json()
    print(f"Status: {task['status']}")

    if task["status"] in ("succeeded", "failed", "cancelled"):
        break
    time.sleep(5)  # poll every 5 seconds

# On success, content contains the video URL
if task["status"] == "succeeded":
    print("Video URL:", task["content"]["video_url"])
elif task["status"] == "failed":
    print("Failed:", task["error"])

Note: The content.video_url is a pre-signed URL with a time-limited expiry (typically 24 hours). Download the video promptly or poll the Get endpoint again to obtain a fresh URL.

Response: Running

{
  "id": "task_01JXN4KQWER5678ABCDEFGH",
  "object": "video.generation.task",
  "created": 1748160000,
  "model": "byteplus/seedance-2.0",
  "status": "running",
  "updated_at": 1748160012
}

Response: Succeeded

{
  "id": "cgt-20260526115001-ldvq4",
  "object": "video.generation.task",
  "created": 1779767402,
  "model": "byteplus/seedance-2.0",
  "status": "succeeded",
  "updated_at": 1779767585,
  "completed_at": 1779767585,
  "content": {
    "video_url": "https://ark-acg-ap-southeast-1.tos-ap-southeast-1.volces.com/dreamina-seedance-2-0/example.mp4?X-Tos-Algorithm=TOS4-HMAC-SHA256&..."
  },
  "metadata": {}
}

Note: The content field contains upstream-defined payload. For succeeded tasks, it typically has a video_url field with a pre-signed download URL. The URL is time-limited (usually 24 hours) — download promptly or use the Get endpoint to obtain a fresh URL.

Response: Failed

{
  "id": "task_01JXN4KQWER5678ABCDEFGH",
  "object": "video.generation.task",
  "created": 1748160000,
  "model": "byteplus/seedance-2.0",
  "status": "failed",
  "updated_at": 1748160045,
  "completed_at": 1748160045,
  "error": {
    "code": "content_policy_violation",
    "message": "The prompt was rejected due to content policy.",
    "type": "video_generation_error",
    "param": null
  }
}

List Video Generations

GET /v1/video/generations

List all non-deleted video generation tasks for the authenticated API key. This endpoint reads from Pomex storage only and does not synchronize with upstream. Results are ordered by created_at DESC, task_id DESC and support cursor-based pagination.

Query Parameters

Parameter Type Default Description
limit integer 20 Number of tasks to return. Omitted or 0 becomes 20. Values above 100 are capped at 100. Negative or non-integer values return 400.
cursor string — Opaque pagination cursor from a previous response's next_cursor.

Example Request

curl "https://api.pomex.ai/v1/video/generations?limit=5" \
  -H "Authorization: Bearer $POMEX_API_KEY"

Response

{
  "object": "list",
  "data": [
    {
      "id": "task_01JXN4KQWER5678ABCDEFGH",
      "object": "video.generation.task",
      "created": 1748160000,
  "model": "byteplus/seedance-2.0",
  "status": "succeeded",
  "completed_at": 1748160090
    },
    {
      "id": "task_01JXN3ABCDEF1234567890",
      "object": "video.generation.task",
      "created": 1748159000,
      "model": "byteplus/seedance-2.0",
      "status": "running"
    }
  ],
  "has_more": true,
  "next_cursor": "eyJjIjoiMjAyNi0wNS0yNVQxMDowMDowMFoifQ"
}

Delete Video Generation

DELETE /v1/video/generations/{task_id}

Delete a video generation task. Pomex first calls upstream DELETE, then soft-deletes the local task row and returns a compact delete response.

If upstream returns a final snapshot during delete, Pomex will merge that snapshot and attempt terminal billing settlement before soft deletion.

Path Parameters

Parameter Type Description
task_id string The task identifier to delete.

Example Request

curl -X DELETE https://api.pomex.ai/v1/video/generations/task_01JXN4KQWER5678ABCDEFGH \
  -H "Authorization: Bearer $POMEX_API_KEY"

Response (200 OK)

{
  "id": "task_01JXN4KQWER5678ABCDEFGH",
  "object": "video.generation.task",
  "deleted": true
}

Webhook Callback

If you provide a callback_url in the Create request, Pomex stores it and may send a POST request when the task reaches a terminal state. The request body is the same task JSON returned by the Get endpoint.

Delivery rules: only HTTPS callback URLs are delivered. The current default retry config is 3 attempts total (initial try plus 2 retries) with backoff delays of 1s and 3s. Network errors and 5xx responses are retried; 4xx responses are not retried.

Callback Request Body

POST https://yourapp.example.com/webhooks/video-done
Content-Type: application/json

{
  "id": "task_01JXN4KQWER5678ABCDEFGH",
  "object": "video.generation.task",
  "created": 1748160000,
  "model": "byteplus/seedance-2.0",
  "status": "succeeded",
  "completed_at": 1748160090,
  "content": {
    "video_url": "https://ark-acg-ap-southeast-1.tos-ap-southeast-1.volces.com/dreamina-seedance-2-0/example.mp4?X-Tos-Algorithm=TOS4-HMAC-SHA256&..."
  },
  "metadata": {"project": "music-video", "scene": 3}
}

Complete Workflow Example

Here's a full Python example that creates a video, polls for completion, and downloads the result:

import time
import requests

API_KEY = "YOUR_API_KEY"
BASE_URL = "https://api.pomex.ai"
headers = {"Authorization": f"Bearer {API_KEY}", "Content-Type": "application/json"}

# Step 1: Create the video generation task
create_resp = requests.post(
    f"{BASE_URL}/v1/video/generations",
    headers=headers,
    json={
        "model": "byteplus/seedance-2.0",
        "content": [
            {"type": "text", "text": "A serene ocean wave crashing on a rocky shore at golden hour, 4K cinematic"},
            {
                "type": "image_url",
                "role": "reference_image",
                "image_url": {"url": "https://example.com/beach-reference.jpg"},
            },
        ],
        "duration": 10,
        "ratio": "16:9",
        "resolution": "1080p",
        "generate_audio": True,
    },
)
create_resp.raise_for_status()
task = create_resp.json()
task_id = task["id"]
print(f"Task created: {task_id} (status: {task['status']})")

# Step 2: Poll until terminal state
while task["status"] not in ("succeeded", "failed", "cancelled"):
    time.sleep(5)
    poll_resp = requests.get(f"{BASE_URL}/v1/video/generations/{task_id}", headers=headers)
    poll_resp.raise_for_status()
    task = poll_resp.json()
    print(f"  Status: {task['status']}")

# Step 3: Handle result
if task["status"] == "succeeded":
    video_url = task["content"]["video_url"]
    print(f"Video URL: {video_url}")

    # Download the video (URL is time-limited, typically 24h)
    video_data = requests.get(video_url).content
    with open("output.mp4", "wb") as f:
        f.write(video_data)
    print("Saved to output.mp4")

elif task["status"] == "failed":
    print(f"Generation failed: {task['error']['message']}")

elif task["status"] == "cancelled":
    print("Task was cancelled")

Error Responses

Error responses use the same top-level OpenAI-style error envelope as the rest of Pomex. The exact type string varies by code path, so the table below focuses on status and trigger conditions that are confirmed in the implementation.

{
  "error": {
    "message": "content must contain at least one item",
    "type": "invalid_request_error",
    "param": null,
    "code": null
  }
}
HTTP Status Cause
400 Invalid request body, missing model, empty content, invalid list cursor, invalid list limit, missing task_id, or sanitized request with no valid content items remaining.
401 Missing or invalid API key
402 Insufficient credit balance for prepaid accounts
404 Unsupported model on create, or task_id not found for get/delete
413 Request body too large
429 Rate limit exceeded during create
503 Store/upstream not configured, billing unavailable, persistence failure, or other service-side dependency failure

Video Assets

The Video Assets API allows you to upload media files (images, videos, audio) to the asset library for use as references in video generation. Assets are uploaded via URL, processed and moderated by upstream, then become available for use in generation requests.

Endpoint Method Description
/v1/video/assets POST Create (upload) a new asset
/v1/video/assets/{asset_id} GET Get asset status and details

Asset Status Lifecycle

Status Description
processing Asset uploaded and being processed/moderated by upstream
active Asset is ready for use in video generation requests
failed Processing or moderation failed — see error field for details

Create Asset

POST /v1/video/assets

Upload a media file by providing its HTTPS URL. The asset will be processed and moderated by the upstream service. The response returns immediately with the asset ID and a processing status.

Request Body Parameters

Parameter Type Required Description
url string Yes HTTPS URL of the media file to upload. Must be a valid https:// URL.
asset_type string Yes Type of the asset. Must be one of: "Image", "Video", "Audio" (case-sensitive).
name string No Optional human-readable name for the asset. Maximum 64 characters.

Example Request

curl https://api.pomex.ai/v1/video/assets \
  -H "Authorization: Bearer $POMEX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://example.com/my-reference-image.jpg",
    "asset_type": "Image",
    "name": "Beach portrait reference"
  }'
import requests

resp = requests.post(
    "https://api.pomex.ai/v1/video/assets",
    headers={
        "Authorization": "Bearer YOUR_API_KEY",
        "Content-Type": "application/json",
    },
    json={
        "url": "https://example.com/my-reference-image.jpg",
        "asset_type": "Image",
        "name": "Beach portrait reference",
    },
)

asset = resp.json()
print(asset["id"], asset["status"])
# → "asset_abc123..." "processing"

Response (200 OK)

{
  "id": "asset_01JXN5ABC1234567890DEF",
  "object": "video.asset",
  "status": "processing"
}

Get Asset

GET /v1/video/assets/{asset_id}

Retrieve the current status and details of an asset. Poll this endpoint to check when an asset becomes active and ready for use in video generation requests.

Path Parameters

Parameter Type Description
asset_id string The unique asset identifier returned by the Create endpoint.

Example Request

curl https://api.pomex.ai/v1/video/assets/asset_01JXN5ABC1234567890DEF \
  -H "Authorization: Bearer $POMEX_API_KEY"

Response: Processing

{
  "id": "asset_01JXN5ABC1234567890DEF",
  "object": "video.asset",
  "name": "Beach portrait reference",
  "asset_type": "Image",
  "status": "processing",
  "created_at": "2026-05-25T10:00:00Z",
  "updated_at": "2026-05-25T10:00:00Z"
}

Response: Active

{
  "id": "asset_01JXN5ABC1234567890DEF",
  "object": "video.asset",
  "name": "Beach portrait reference",
  "url": "https://cdn.example.com/assets/processed_abc123.jpg",
  "asset_type": "Image",
  "status": "active",
  "created_at": "2026-05-25T10:00:00Z",
  "updated_at": "2026-05-25T10:00:15Z"
}

Response: Failed

{
  "id": "asset_01JXN5ABC1234567890DEF",
  "object": "video.asset",
  "name": "Beach portrait reference",
  "asset_type": "Image",
  "status": "failed",
  "error": {
    "code": "moderation_rejected",
    "message": "Asset rejected during content moderation"
  },
  "created_at": "2026-05-25T10:00:00Z",
  "updated_at": "2026-05-25T10:00:20Z"
}

Asset Error Responses

HTTP Status Cause
400 Missing or invalid url (must be HTTPS), missing or invalid asset_type (must be Image/Video/Audio), name exceeds 64 characters, missing asset_id in path
401 Missing or invalid API key
404 Asset not found (wrong asset_id or asset belongs to a different organization)
413 Request body too large
503 Asset service unavailable, organization asset library not configured, admin credentials not configured, upstream failure, or persistence failure

Using Assets in Video Generation

Once an asset reaches active status, use the asset://{asset_id} protocol URL in your video generation request's media fields. The gateway resolves the asset reference automatically:

# Step 1: Create an image asset
curl https://api.pomex.ai/v1/video/assets \
  -H "Authorization: Bearer $POMEX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://example.com/my-portrait.jpg",
    "asset_type": "Image",
    "name": "Portrait reference"
  }'
# → {"id":"asset-20260524233646-v76gs","object":"video.asset","status":"processing"}

# Step 2: Poll until active
curl https://api.pomex.ai/v1/video/assets/asset-20260524233646-v76gs \
  -H "Authorization: Bearer $POMEX_API_KEY"
# → {"id":"asset-20260524233646-v76gs","object":"video.asset","status":"active",...}

# Step 3: Use asset:// protocol URL in video generation
curl https://api.pomex.ai/v1/video/generations \
  -H "Authorization: Bearer $POMEX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "byteplus/seedance-2.0",
    "content": [
      {
        "type": "text",
        "text": "The person slowly turns their head and smiles warmly at the camera"
      },
      {
        "type": "image_url",
        "role": "reference_image",
        "image_url": {
          "url": "asset://asset-20260524233646-v76gs"
        }
      }
    ],
    "duration": 5,
    "ratio": "9:16"
  }'
import time
import requests

API_KEY = "YOUR_API_KEY"
BASE_URL = "https://api.pomex.ai"
headers = {"Authorization": f"Bearer {API_KEY}", "Content-Type": "application/json"}

# Step 1: Upload an image asset
asset_resp = requests.post(
    f"{BASE_URL}/v1/video/assets",
    headers=headers,
    json={
        "url": "https://example.com/my-portrait.jpg",
        "asset_type": "Image",
        "name": "Portrait reference",
    },
)
asset_resp.raise_for_status()
asset_id = asset_resp.json()["id"]
print(f"Asset created: {asset_id}")

# Step 2: Poll until the asset is active
while True:
    get_resp = requests.get(f"{BASE_URL}/v1/video/assets/{asset_id}", headers=headers)
    get_resp.raise_for_status()
    asset = get_resp.json()
    print(f"  Asset status: {asset['status']}")
    if asset["status"] == "active":
        break
    elif asset["status"] == "failed":
        raise RuntimeError(f"Asset failed: {asset.get('error', {}).get('message')}")
    time.sleep(3)

print(f"Asset ready: {asset_id}")

# Step 3: Use asset:// protocol URL in video generation
gen_resp = requests.post(
    f"{BASE_URL}/v1/video/generations",
    headers=headers,
    json={
        "model": "byteplus/seedance-2.0",
        "content": [
            {
                "type": "text",
                "text": "The person slowly turns their head and smiles warmly at the camera",
            },
            {
                "type": "image_url",
                "role": "reference_image",
                "image_url": {"url": f"asset://{asset_id}"},
            },
        ],
        "duration": 5,
        "ratio": "9:16",
    },
)
gen_resp.raise_for_status()
task = gen_resp.json()
print(f"Video task created: {task['id']} (status: {task['status']})")

# Step 4: Poll video generation until complete
while task["status"] not in ("succeeded", "failed", "cancelled"):
    time.sleep(5)
    poll_resp = requests.get(f"{BASE_URL}/v1/video/generations/{task['id']}", headers=headers)
    poll_resp.raise_for_status()
    task = poll_resp.json()
    print(f"  Video status: {task['status']}")

if task["status"] == "succeeded":
    print("Video URL:", task["content"]["video_url"])

Key point: Use the asset://{asset_id} protocol URL to reference uploaded assets in video generation requests. The gateway resolves asset references to the underlying processed media automatically. You can also use direct HTTPS URLs to publicly accessible media without creating assets first.

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