def _registerInterface(self, iName, intf, isPrivate=False):
        """
        Register interface object on interface level object
        """
        nameAvailabilityCheck(self, iName, intf)
        assert intf._parent is None
        intf._parent = self
        intf._name = iName
        intf._ctx = self._ctx

        if isPrivate:
            self._private_interfaces.append(intf)
            intf._isExtern = False
        else:
            self._interfaces.append(intf)
            intf._isExtern = True
Register interface object on interface level object