feat(announcements): optional announcement_expired_at field (DES-1500)

[pete-sw]

Summary

Adds announcement_expired_at support to the announcement API, matching the new field added to the Atlan platform in DES-1500.

Changes

pyatlan/model/core.py

• Added from datetime import datetime import
• Added announcement_expired_at: Optional[datetime] field to Announcement dataclass (optional, defaults to None — fully backward compatible)

pyatlan/model/assets/core/asset.py

• Added announcement_expired_at: Optional[datetime] to Asset.Attributes
• Added announcement_expired_at to the attribute fetch list (required for the field to be populated when loading assets from the API)
• Added property getter/setter on Asset
• Updated set_announcement() to set the field
• Updated get_announcment() to return the field
• Updated Attributes.remove_announcement() to null the field

Usage

from datetime import datetime, timezone
from pyatlan.model.core import Announcement
from pyatlan.model.enums import AnnouncementType

# With expiration date
announcement = Announcement(
    announcement_title="Caution",
    announcement_message="This table is being deprecated.",
    announcement_type=AnnouncementType.WARNING,
    announcement_expired_at=datetime(2026, 6, 1, tzinfo=timezone.utc),
)

# Without expiration date (unchanged from before)
announcement = Announcement(
    announcement_title="Caution",
    announcement_type=AnnouncementType.WARNING,
)

Test plan

• Existing announcement tests pass (backward compatible)
• Announcement can be created without announcement_expired_at
• set_announcement() / get_announcment() round-trip preserves announcement_expired_at
• remove_announcement() clears announcement_expired_at
• Field is included in API fetch results

🤖 Generated with Claude Code

[greptile-apps]

Greptile Summary

This PR adds optional expiration date support to announcement API through the announcement_expired_at field.

Key Changes

• Added announcement_expired_at: Optional[datetime] to Announcement dataclass and Asset.Attributes
• Integrated field throughout announcement lifecycle: set_announcement(), get_announcment(), remove_announcement()
• Added field to asset fetch list to ensure API population
• Added property getter/setter on Asset following existing patterns

Implementation Quality

• Fully backward compatible - field is optional with None default
• Follows existing codebase patterns for datetime fields (matches announcement_updated_at)
• Proper datetime serialization handled via Pydantic encoders (converts to milliseconds since epoch)
• Consistent integration across all announcement-related methods
• Clean implementation with appropriate imports and type hints

Confidence Score: 5/5

• This PR is safe to merge with minimal risk
• Score reflects clean implementation following established patterns, full backward compatibility, proper datetime handling, and comprehensive integration across all announcement methods
• No files require special attention

Important Files Changed

Filename	Overview
pyatlan/model/core.py	Added optional announcement_expired_at datetime field to Announcement dataclass with proper imports and default value
pyatlan/model/assets/core/asset.py	Integrated announcement_expired_at throughout asset model - added to attributes, fetch list, property getter/setter, and all announcement methods

_{Last reviewed commit: 1bc740a}