code: def _add_to_schema(self, field_name, schema):
          
          super(ForeignKeyField, self)._add_to_schema(field_name, schema)
  
          if self.get_field_value('convert_fks', default=True):
              self.attribute = field_name.replace('_id', '')
docs: Set the ``attribute`` attr to the field in question so this always
          gets deserialzed into the field name without ``_id``.
  
          Args:
              field_name (str): The name of the field (the attribute name being
                  set in the schema).
              schema (marshmallow.Schema): The actual parent schema this field
                 belongs to.