'Merges beacon information in the adapter state (if it exists) into
the provided beacon information. Specifically, this merges used and
seen beacons.
If the adapter state has no beacon information, does nothing.
@param beaconInformation: The beacon information object that beacon
information will be merged into (if necessary).
@type beaconInformation: L{twisted.positioning.base.BeaconInformation}'

def _mergeBeaconInformation(self, newBeaconInformation):

    old = self._state.get('_partialBeaconInformation')
    if (old is None):
        return
    for attr in ['seenBeacons', 'usedBeacons']:
        getattr(newBeaconInformation, attr).update(getattr(old, attr))
