from PySide6.QtCore import QObject, Signal

class Emitter(QObject):
    sig = Signal(int)

class CallableObject(QObject):
    def __call__(self, x: int):
        print("emitting", locals())

emitter = Emitter()
obj = CallableObject()

emitter.sig.connect(obj)
emitter.sig.emit(1)

Traceback (most recent call last):
  File "/Users/talley/dev/self/superqt/x.py", line 16, in <module>
    emitter.sig.connect(obj)
TypeError: 'PySide6.QtCore.QObject.connect' called with wrong argument types:
  PySide6.QtCore.QObject.connect(Emitter, str, CallableObject)
Supported signatures:
  PySide6.QtCore.QObject.connect(PySide6.QtCore.QObject, Union[bytes, bytearray, memoryview], Union[bytes, bytearray, memoryview], PySide6.QtCore.Qt.ConnectionType = Instance(Qt.AutoConnection))
  PySide6.QtCore.QObject.connect(Union[bytes, bytearray, memoryview], Callable, PySide6.QtCore.Qt.ConnectionType = Instance(Qt.AutoConnection))
  PySide6.QtCore.QObject.connect(Union[bytes, bytearray, memoryview], PySide6.QtCore.QObject, Union[bytes, bytearray, memoryview], PySide6.QtCore.Qt.ConnectionType = Instance(Qt.AutoConnection))
  PySide6.QtCore.QObject.connect(PySide6.QtCore.QObject, PySide6.QtCore.QMetaMethod, PySide6.QtCore.QObject, PySide6.QtCore.QMetaMethod, PySide6.QtCore.Qt.ConnectionType = Instance(Qt.AutoConnection))
  PySide6.QtCore.QObject.connect(PySide6.QtCore.QObject, Union[bytes, bytearray, memoryview], PySide6.QtCore.QObject, Callable, PySide6.QtCore.Qt.ConnectionType = Instance(Qt.AutoConnection))
  PySide6.QtCore.QObject.connect(PySide6.QtCore.QObject, Union[bytes, bytearray, memoryview], Callable, PySide6.QtCore.Qt.ConnectionType = Instance(Qt.AutoConnection))
  PySide6.QtCore.QObject.connect(PySide6.QtCore.QObject, Union[bytes, bytearray, memoryview], PySide6.QtCore.QObject, Union[bytes, bytearray, memoryview], PySide6.QtCore.Qt.ConnectionType = Instance(Qt.AutoConnection))