code: def uncache(self, name):
          
          delme = []
          if self._is_pattern(name):
              expr = re.compile(self._pattern_to_regex(name))
              for key, obj in self._cached.items():
                  if expr.match(key):
                      delme.append(key)
          else:
              if name in self._cached:
                  delme.append(name)
          for key in delme:
              del self._cached[key]
docs: Remove all created query engines that match `name` from
          the cache (this disconnects from MongoDB, which is the point).
  
          :param name: Name used for :meth:`add`, or pattern
          :return: None