def __call__(cls, *args, **kwargs):
<EOL>if issubclass(cls, ComponentManager):<EOL><INDENT>self = cls.__new__(cls)<EOL>self.compmgr = self<EOL>self.__init__(*args, **kwargs)<EOL>return self<EOL><DEDENT>msg = "<STR_LIT>"<EOL>assert len(args) >= <NUM_LIT:1> and isinstance(args[<NUM_LIT:0>], ComponentManager), msg<EOL>compmgr = args[<NUM_LIT:0>]<EOL>self = compmgr.components.get(cls)<EOL>if self is None:<EOL><INDENT>self = cls.__new__(cls)<EOL>self.compmgr = compmgr<EOL>compmgr.component_activated(self)<EOL>self.__init__()<EOL>compmgr.components[cls] = self<EOL><DEDENT>return self<EOL>
Return an existing instance of the component if it has
        already been activated, otherwise create a new instance.