'Change the current IP version setting.
.. note:: This method is the slot responses to the signal argument
:attr:`ipv_id` from SelectIP widget while the value is changed.
:param ipv_id: An flag indicating current IP version setting. The
value could be 1 or 0:
ipv_id  IP Version
1       IPv6
0       IPv4
:type ipv_id: int'

def on_IPVersion_changed(self, ipv_id):

    if (self._ipv_id != ipv_id):
        self._ipv_id = ipv_id
        if (not RetrieveData.db_exists()):
            self.warning_no_datafile()
        else:
            self.set_func_list(0)
            self.refresh_func_list()
