code: def get_cached(self, link, default=None):
          '''Retrieves a cached navigator from the id_map.
  
          Either a Link object or a bare uri string may be passed in.'''
          if hasattr(link, 'uri'):
              return self.id_map.get(link.uri, default)
          else:
              return self.id_map.get(link, defaultf get_cached(self, link, default=None):
          '''Retrieves a cached navigator from the id_map.
  
          Either a Link object or a bare uri string may be passed in.'''
          if hasattr(link, 'uri'):
              return self.id_map.get(link.uri, default)
          else:
              return self.id_map.get(link, default)
docs: Retrieves a cached navigator from the id_map.
  
          Either a Link object or a bare uri string may be passed in.