docs: def to_funset(self):
          """
          Converts the hypergraph to a set of `gringo.Fun`_ instances
  
          Returns
          -------
          set
              Representation of the hypergraph as a set of `gringo.Fun`_ instances
  
  
          .. _gringo.Fun: http://potassco.sourceforge.net/gringo.html#Fun
          """
          fs = set()
          for i, n in self.nodes.iteritems():
              fs.add(gringo.Fun('node', [n, i]))
  
          for j, i in self.hyper.iteritems():
              fs.add(gringo.Fun('hyper', [i, j, len(self.edges[self.edges.hyper_idx == j])]))
  
          for j, v, s in self.edges.itertuples(index=False):
              fs.add(gringo.Fun('edge', [j, v, s]))
  
          return fs