Callbacks

Some constant and some very simple callbacks.

Constant callbacks

• constant(), factory that creates an instance, that always returns the initial value. Equivalent to lambda x: value.

• return_True(), equivalent to lambda x: True.

• return_False(), equivalent to lambda x: False.

• return_None(), equivalent to lambda x: None.

Simple callbacks

• packed(), equivalent to lambda func: lambda x: func(*x).

• return_identity(), equivalent to lambda x: x.

• return_first_arg(), equivalent to lambda *args, **kwargs: args[0].

• return_called(), equivalent to lambda x: x().