def _warn_for_federation_directives(self) -> None:
        """Raises a warning if the schema has any federation directives."""
        from strawberry.federation.schema_directives import FederationDirective

        all_types = self.schema_converter.type_map.values()
        all_type_defs = (type_.definition for type_ in all_types)

        all_directives = (
            directive
            for type_def in all_type_defs
            for directive in (type_def.directives or [])
        )

        if any(
            isinstance(directive, FederationDirective) for directive in all_directives
        ):
            warnings.warn(
                "Federation directive found in schema. "
                "Use `strawberry.federation.Schema` instead of `strawberry.Schema`.",
                UserWarning,
                stacklevel=3,
            )
Raises a warning if the schema has any federation directives.
strawberry/schema/schema.py