def METHOD_NAME(
    self,
    collab_name: str,
    delta: FetchDeltaTyped,
) -> None:
    file = self.collab_file(collab_name)
    if not file.parent.exists():
        file.parent.mkdir(parents=True)
    if issubclass(self.api_cls, SignalExchangeAPIWithSimpleUpdates):
        record_sanity_check = next(
            (record for record in delta.updates.values()),
            None,
        )
        if record_sanity_check is not None:
            assert (  # Not isinstance - we want exactly this class
                record_sanity_check.__class__ == self.api_cls.get_record_cls()
            ), (
                f"Record cls: want {self.api_cls.get_record_cls().__name__} "
                f"got {record_sanity_check.__class__.__name__}"
            )
    tmpfile = file.with_name(f".{file.name}")
    with tmpfile.open("wb") as f:
        pickle.dump(delta, f)
    tmpfile.rename(file)