code: def getFieldMax(self, fieldName):
      
      stats = self.getStats()
      if stats == None:
        return None
      maxValues = stats.get('max', None)
      if maxValues == None:
        return None
      index = self.getFieldNames().index(fieldName)
      return maxValues[index]
docs: If underlying implementation does not support min/max stats collection,
      or if a field type does not support min/max (non scalars), the return
      value will be None.
  
      :param fieldName: (string) name of field to get max
      :returns: current maximum value for the field ``fieldName``.