def getComponent(self, interface, default=None):
        """Create or retrieve an adapter for the given interface.

        If such an adapter has already been created, retrieve it from the cache
        that this instance keeps of all its adapters.  Adapters created through
        this mechanism may safely store system-specific state.

        If you want to register an adapter that will be created through
        getComponent, but you don't require (or don't want) your adapter to be
        cached and kept alive for the lifetime of this Componentized object,
        set the attribute 'temporaryAdapter' to True on your adapter class.

        If you want to automatically register an adapter for all appropriate
        interfaces (with addComponent), set the attribute 'multiComponent' to
        True on your adapter class.
        """
        k = reflect.qual(interface)
        if k in self._adapterCache:
            return self._adapterCache[k]
        else:
            adapter = interface.__adapt__(self)
            if adapter is not None and not (
                hasattr(adapter, "temporaryAdapter") and
                adapter.temporaryAdapter):
                self._adapterCache[k] = adapter
                if (hasattr(adapter, "multiComponent") and
                    adapter.multiComponent):
                    self.addComponent(adapter)
            if adapter is None:
                return default
            return adapter
Create or retrieve an adapter for the given interface.

        If such an adapter has already been created, retrieve it from the cache
        that this instance keeps of all its adapters.  Adapters created through
        this mechanism may safely store system-specific state.

        If you want to register an adapter that will be created through
        getComponent, but you don't require (or don't want) your adapter to be
        cached and kept alive for the lifetime of this Componentized object,
        set the attribute 'temporaryAdapter' to True on your adapter class.

        If you want to automatically register an adapter for all appropriate
        interfaces (with addComponent), set the attribute 'multiComponent' to
        True on your adapter class.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/components.py