code: def get(self, tzid=None):
          
          if tzid is None:
              if len(self._vtz) == 0:
                  raise ValueError("no timezones defined")
              elif len(self._vtz) > 1:
                  raise ValueError("more than one timezone available")
              tzid = next(iter(self._vtz))
  
          return self._vtz.get(tzid)
docs: Retrieve a :py:class:`datetime.tzinfo` object by its ``tzid``.
  
          :param tzid:
              If there is exactly one time zone available, omitting ``tzid``
              or passing :py:const:`None` value returns it. Otherwise a valid
              key (which can be retrieved from :func:`keys`) is required.
  
          :raises ValueError:
              Raised if ``tzid`` is not specified but there are either more
              or fewer than 1 zone defined.
  
          :returns:
              Returns either a :py:class:`datetime.tzinfo` object representing
              the relevant time zone or :py:const:`None` if the ``tzid`` was
              not found.