whole_func_string: function undirEdgeId(u, v) {
      return u < v
        ? u.toString().length + ':' + u + '-' + v
        : v.toString().length + ':' + v + '-' + u;
    }
func_code_string: function undirEdgeId(u, v) {
      return u < v
        ? u.toString().length + ':' + u + '-' + v
        : v.toString().length + ':' + v + '-' + u;
    }
func_documentation_string: /*
  Generate an ID that can be used to represent any undirected edge that is
  incident on `u` and `v`.