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

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)

from gaphas.guide import GuidedItemInMotion
from gaphor.core import inject, Transaction, transactional

from gaphor.diagram.interfaces import IEditor, IConnect, IGroup
from gaphor.diagram.diagramline import DiagramLine
from gaphor.diagram.elementitem import ElementItem


# cursor to indicate grouping
IN_CURSOR = gtk.gdk.Cursor(gtk.gdk.DIAMOND_CROSS)

# cursor to indicate ungrouping
OUT_CURSOR = gtk.gdk.Cursor(gtk.gdk.SIZING)


@Connector.when_type(DiagramLine)
class DiagramItemConnector(Connector.default):
    """
    Handle Tool (acts on item handles) that uses the IConnect protocol
    to connect items to one-another.

    It also adds handles to lines when a line is grabbed on the middle of
    a line segment (points are drawn by the LineSegmentPainter).
    """

    def allow(self, sink):
        adapter = component.queryMultiAdapter((sink.item, self.item), IConnect)
        return adapter and adapter.allow(self.handle, sink.port)


    @transactional
    def connect(self, sink):

from gaphor.core import Transaction, transactional
from gaphor.diagram.connectors import IConnect
from gaphor.diagram.grouping import Group
from gaphor.diagram.inlineeditors import InlineEditor
from gaphor.diagram.presentation import ElementPresentation, LinePresentation

# cursor to indicate grouping
IN_CURSOR_TYPE = Gdk.CursorType.DIAMOND_CROSS

# cursor to indicate ungrouping
OUT_CURSOR_TYPE = Gdk.CursorType.CROSSHAIR

log = logging.getLogger(__name__)


@Connector.register(LinePresentation)
class DiagramItemConnector(ItemConnector):
    """
    Handle Tool (acts on item handles) that uses the IConnect protocol
    to connect items to one-another.

    It also adds handles to lines when a line is grabbed on the middle of
    a line segment (points are drawn by the LineSegmentPainter).
    """

    def allow(self, sink):
        adapter = IConnect(sink.item, self.item)
        return adapter and adapter.allow(self.handle, sink.port)

    @transactional
    def connect(self, 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)

def _postload_connect(self, handle, item):
        """
        Postload connect method.
        """
        from gaphas.aspect import Connector

        connector = Connector(self, handle)

        sink = self._get_sink(handle, item)

        connector.connect(sink)

def postload_connect(handle, item):
            connector = gaphas.aspect.Connector(self, handle)
            sink = get_sink(handle, item)
            connector.connect(sink)