langchain/tools/openapi/utils/api_models.py/APIProperty/_get_schema_type
class APIProperty:    def _get_schema_type(parameter: Parameter, schema: Optional[Schema]) -> SCHEMA_TYPE:
        if schema is None:
            return None
        schema_type: SCHEMA_TYPE = APIProperty._cast_schema_list_type(schema)
        if schema_type == "array":
            schema_type = APIProperty._get_schema_type_for_array(schema)
        elif schema_type == "object":
            # TODO: Resolve array and object types to components.
            raise NotImplementedError("Objects not yet supported")
        elif schema_type in PRIMITIVE_TYPES:
            if schema.enum:
                schema_type = APIProperty._get_schema_type_for_enum(parameter, schema)
            else:
                # Directly use the primitive type
                pass
        else:
            raise NotImplementedError(f"Unsupported type: {schema_type}")

        return schema_type