Hi,

There seems to be a bug when using user-defined parent selection function. The function should have 3 parameters (or 4 for a method), and that how it is checked when creating the GA instance. But when it runs the algorithm it sends 4 parameters instead of 3 (getting error "_parent_selection_func() takes 3 positional arguments but 4 were given").
As I understand this is due to an extra "self" passed to the parent selection function as a first parameter in line 1750, and removing it should fix it.

Thanks