code: def nrefs(self, tag):
          
  
          n = _C.Vnrefs(self._id, tag)
          _checkErr('nrefs', n, "bad arguments")
          return n
docs: Determine the number of tags of a given type in a vgroup.
  
          Args::
  
            tag    tag type to look for in the vgroup
  
          Returns::
  
            number of members identified by this tag type
  
          C library equivalent : Vnrefs