'Get a dict of port names and associated vlan tags.
e.g. the returned dict is of the following form::
{u\'int-br-eth2\': [],
u\'patch-tun\': [],
u\'qr-76d9e6b6-21\': 1,
u\'tapce5318ff-78\': 1,
u\'tape1400310-e6\': 1}
The TAG ID is only available in the "Port" table and is not available
in the "Interface" table queried by the get_vif_port_set() method.'

def get_port_tag_dict(self):

    results = self.get_ports_attributes('Port', columns=['name', 'tag'], if_exists=True)
    return {p['name']: p['tag'] for p in results}
