parse_artifact_update

def parse_artifact_update(update: TaskArtifactUpdateEvent) -> A2ATaskArtifactUpdate:
    """Pick the most specific ``A2ATaskArtifactUpdate`` subclass for an update.

    Returns ``A2ATextArtifact`` for text-only artifacts, ``A2AToolCallArtifact``
    for AG2 ``tool-call+json`` extension parts, and the base
    ``A2ATaskArtifactUpdate`` for any other shape.
    """
    artifact = update.artifact
    parts = list(artifact.parts)
    text_only = parts and all(bool(p.text) for p in parts)
    if text_only:
        return A2ATextArtifact(
            update=update,
            append=update.append,
            last_chunk=update.last_chunk,
            text="".join(p.text for p in parts),
        )

    if len(parts) == 1 and is_data_part_with_mime(parts[0], MIME_TOOL_CALL):
        return A2AToolCallArtifact(
            update=update,
            append=update.append,
            last_chunk=update.last_chunk,
            call=payload_to_call(part_data_to_python(parts[0])),
        )

    return A2ATaskArtifactUpdate(
        update=update,
        append=update.append,
        last_chunk=update.last_chunk,
    )