code: def list_registered_stateful_ops_without_inputs():
    
    return set([
        name
        for name, op in op_def_registry.get_registered_ops().items()
        if op.is_stateful and not op.input_arg
    ])
docs: Returns set of registered stateful ops that do not expect inputs.
  
    This list is used to identify the ops to be included in the state-graph and
    that are subsequently fed into the apply-graphs.
  
    Returns:
      A set of strings.