Signal inheritance from multiple base classes

[olumide]

The docs appear to show that GTK can inherit inherit signals from multiple base classes, yet in the following example creates a runtime error because the signal name in the second inherited base class inherited is not found. Am I missing a special syntax?

import gi

gi.require_version("Gtk", "3.0")
from gi.repository import GObject

class Child1(GObject.GObject):
    __gsignals__ = {
        "one": (GObject.SignalFlags.RUN_LAST, None, ()),
    }
    
    def __init__(self):
        GObject.GObject.__init__(self)


class Child2(GObject.GObject):
    __gsignals__ = {
        "two": (GObject.SignalFlags.RUN_LAST, None, ()),
    }
    
    def __init__(self):
        GObject.GObject.__init__(self)


class Parent(Child1, Child2):
    def __init__(self):
        Child1.__init__(self)
        Child2.__init__(self)


class Foo(GObject.GObject):
    def __init__(self):
        GObject.GObject.__init__(self)
    
    def func(self, _):
        pass

if __name__ == "__main__":
    foo = Foo()
    parent = Parent()
    parent.connect("one", foo.func) # OK
    parent.connect("two", foo.func) # fails

Error

Traceback (most recent call last):
  File "./TestSignal_Inheritance.py", line 41, in <module>
    parent.connect("two", foo.func) # fails
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: <__main__.Parent object at 0x0000022bd705a380 (__main__+Parent at 0x0000022bd54c20e0)>: unknown signal name: two

[ebassi (Emmanuele Bassi)]

GObject does not support multiple inheritance, so Parent cannot inherit from both Child1 and Child2.

GObject uses interfaces for multiple inheritance, but you cannot define an interface in pygobject, AFAIK.