class_docstr: A property generator. The generated property describes an object
  attribute that corresponds to an :class:`_types.Indexable`
  column.
  
  .. seealso::
  
      :mod:`sqlalchemy.ext.indexable`
class_docstr_tok: ["A","property","generator",".","The","generated","property","describes","an","object","attribute","that","corresponds","to","an",":","class",":","`","_types.Indexable","`","column",".","..","seealso",":",":",":","mod",":","`","sqlalchemy.ext.indexable","`"]
code: def fdel(self, instance):
      attr_name = self.attr_name
      column_value = getattr(instance, attr_name)
      if column_value is None:
          raise AttributeError(self.attr_name)
      try:
          del column_value[self.index]
      except KeyError as err:
          raise AttributeError(self.attr_name) from err
      else:
          setattr(instance, attr_name, column_value)
          flag_modified(instance, attr_name)
  
file_path: sqlalchemy/lib/sqlalchemy/ext/indexable.py
imports: from ..None import inspect
  from ..ext.hybrid import hybrid_property
  from ..orm.attributes import flag_modified
label_desc: Use image node_id 5 for calling the index_property obj's underlying member method code with example usage: obj.fdel(instance) without return types