How to use the gaphas.aspect.ConnectionSink function in gaphas

TODO: figure out if part of this functionality can be provided by
        the storage code.
        """
        from gaphas.aspect import ConnectionSink

        hpos = self.canvas.get_matrix_i2i(self, item).transform_point(*handle.pos)
        port = None
        dist = 10e6
        for p in item.ports():
            pos, d = p.glue(hpos)
            if not port or d < dist:
                port = p
                dist = d

        return ConnectionSink(item, port)

def get_sink(handle, item):
            assert self.canvas

            hpos = self.canvas.get_matrix_i2i(self, item).transform_point(*handle.pos)
            port = None
            dist = 10e6
            for p in item.ports():
                pos, d = p.glue(hpos)
                if not port or d < dist:
                    port = p
                    dist = d

            return gaphas.aspect.ConnectionSink(item, port)

def connect(self, line, handle, item, port=None):
        """
        Connect line's handle to an item.

        If port is not provided, then first port is used.
        """
        canvas = line.canvas

        if port is None and len(item.ports()) > 0:
            port = item.ports()[0]

        sink = ConnectionSink(item, port)
        connector = Connector(line, handle)

        connector.connect(sink)

def connect(self, line, handle, item, port=None):
        """
        Connect line's handle to an item.

        If port is not provided, then first port is used.
        """
        canvas = line.canvas

        if port is None and len(item.ports()) > 0:
            port = item.ports()[0]

        sink = ConnectionSink(item, port)
        connector = Connector(line, handle)

        connector.connect(sink)

if distance is None:
            distance = self.GLUE_DISTANCE

        if not handle.connectable:
            return None

        state_v, port, glue_pos = view.get_port_at_point(pos, distance=distance, exclude=(item,),
                                                         exclude_port_fun=self._exclude_port)

        # check if item and found item can be connected on closest port
        if port is not None:
            assert state_v is not None

            connector = Connector(self.item, self.handle)
            sink = ConnectionSink(state_v, port)

            if connector.allow(sink):
                # transform coordinates from view space to the item space and
                # update position of item's handle
                v2i = view.get_matrix_v2i(item).transform_point
                handle.pos = v2i(*glue_pos)
                return sink
        return None