nodes: 0, module; 1, function_definition; 2, function_name:matrix_index; 3, parameters; 4, block; 5, identifier:user; 6, expression_statement; 7, expression_statement; 8, return_statement; 9, comment:"""
      Returns the keys associated with each axis of the matrices.
  
      The first key is always the name of the current user, followed by the
      sorted names of all the correspondants.
      """; 10, assignment; 11, binary_operator:[user.name] + other_keys; 12, identifier:other_keys; 13, call; 14, list; 15, identifier:other_keys; 16, identifier:sorted; 17, argument_list; 18, attribute; 19, list_comprehension; 20, identifier:user; 21, identifier:name; 22, identifier:k; 23, for_in_clause; 24, if_clause; 25, identifier:k; 26, call; 27, comparison_operator:k != user.name; 28, attribute; 29, argument_list; 30, identifier:k; 31, attribute; 32, attribute; 33, identifier:keys; 34, identifier:user; 35, identifier:name; 36, identifier:user; 37, identifier:network
code: def matrix_index(user):
      """
      Returns the keys associated with each axis of the matrices.
  
      The first key is always the name of the current user, followed by the
      sorted names of all the correspondants.
      """
  
      other_keys = sorted([k for k in user.network.keys() if k != user.name])
      return [user.name] + other_keys