'Create a new hatch pattern'

def _get_hatch(self, gc, rgbFace):

    if (rgbFace is not None):
        rgbFace = tuple(rgbFace)
    edge = gc.get_hatch_color()
    if (edge is not None):
        edge = tuple(edge)
    dictkey = (gc.get_hatch(), rgbFace, edge)
    oid = self._hatchd.get(dictkey)
    if (oid is None):
        oid = self._make_id(u'h', dictkey)
        self._hatchd[dictkey] = ((gc.get_hatch_path(), rgbFace, edge), oid)
    else:
        (_, oid) = oid
    return oid
