feat(models): add parent_event_id to Event

src/polymarket/models/gamma/event.py

@@ -257,6 +257,7 @@ class Event(BaseModel):
     """A Polymarket event."""
 
     id: EventId
+    parent_event_id: EventId | None = Field(default=None, validation_alias="parentEventId")
     ticker: str | None = None
     slug: str | None = None
     title: str | None = None
@@ -309,7 +310,7 @@ def render(self: Event) -> str:
 
         return render(self)
 
-    @field_validator("id", mode="before")
+    @field_validator("id", "parent_event_id", mode="before")
     @classmethod
     def _coerce_id(cls, value: object) -> object:
         return coerce_string_id(value)
@@ -331,6 +332,7 @@ def _normalize_event(cls, value: object) -> object:
 
         return {
             "id": data.get("id"),
+            "parent_event_id": data.get("parentEventId"),
             "ticker": data.get("ticker"),
             "slug": data.get("slug"),
             "title": data.get("title"),

tests/unit/test_gamma_models.py

@@ -414,6 +414,17 @@ def test_event_accepts_integer_id_per_ts_schema() -> None:
     assert event.id == "902661"
 
 
+def test_event_parent_event_id_coerces_integer_to_event_id() -> None:
+    event = Event.parse_response(_minimal_event_payload(parentEventId=570146))
+
+    assert event.parent_event_id == "570146"
+
+
+def test_event_parent_event_id_defaults_to_none() -> None:
+    assert Event.parse_response(_minimal_event_payload()).parent_event_id is None
+    assert Event.parse_response(_minimal_event_payload(parentEventId=None)).parent_event_id is None
+
+
 def test_event_nested_series_accepts_integer_id() -> None:
     event = Event.parse_response(
         _minimal_event_payload(series=[{"id": 7, "slug": "s1", "title": "Series 1"}])