code: def multi_occurrence(self):
          
          max = self.max
          if max is None:
              return False
          if max.isdigit():
              return int(max) > 1
          return max == "unbounded"
docs: Get whether the node has multiple occurrences, i.e. is a I{collection}.
  
          @return: True if it has, False if it has at most 1 occurrence.
          @rtype: boolean