Callbacks --------- Some constant and some very simple callbacks. Constant callbacks ^^^^^^^^^^^^^^^^^^ - :py:func:`~iteration_utilities.constant`, factory that creates an instance, that always returns the initial value. Equivalent to ``lambda x: value``. - :py:func:`~iteration_utilities.return_True`, equivalent to ``lambda x: True``. - :py:func:`~iteration_utilities.return_False`, equivalent to ``lambda x: False``. - :py:func:`~iteration_utilities.return_None`, equivalent to ``lambda x: None``. Simple callbacks ^^^^^^^^^^^^^^^^ - :py:func:`~iteration_utilities.packed`, equivalent to ``lambda func: lambda x: func(*x)``. - :py:func:`~iteration_utilities.return_identity`, equivalent to ``lambda x: x``. - :py:func:`~iteration_utilities.return_first_arg`, equivalent to ``lambda *args, **kwargs: args[0]``. - :py:func:`~iteration_utilities.return_called`, equivalent to ``lambda x: x()``.