def METHOD_NAME(self, device, GrpId):
    """
    remove a device from a group
    """
    if GrpId not in self.ListOfGroups:
        return
    if device not in self.ListOfGroups[GrpId]["Devices"]:
        return
    self.ListOfGroups[GrpId]["Devices"].remove(device)
    if len(self.ListOfGroups[GrpId]["Devices"]) == 0:
        # No devices attached to that Group.
        remove_group(self, GrpId)