code: def get_filter_rule(self, _filter, way='in'):
          
          if isinstance(_filter, zobjects.FilterRule):
              _filter = _filter.name
          for f in self.get_filter_rules(way=way):
              if f.name == _filter:
                  return f
          return None
docs: Return the filter rule
  
          :param: _filter a zobjects.FilterRule or the filter name
          :param: way string discribing if filter is for 'in' or 'out' messages
          :returns: a zobjects.FilterRule