code: def _get_schema(cls, schema):
          
          if isinstance(schema, string_types):
              schema = cls._get_object_from_python_path(schema)
  
          if isclass(schema):
              schema = schema()
  
          if not isinstance(schema, Schema):
              raise TypeError("The schema must be a path to a Marshmallow "
                              "schema or a Marshmallow schema.")
  
          return schema
docs: Method that will fetch a Marshmallow schema flexibly.
  
          Args:
              schema (marshmallow.Schema|str): Either the schema class, an
                  instance of a schema, or a Python path to a schema.
  
          Returns:
              marshmallow.Schema: The desired schema.
  
          Raises:
              TypeError: This is raised if the provided object isn't
                  a Marshmallow schema.