Marteen Ter Huurne reported :

If I run PyLint on the following program:

def radixSort(elements, keyFuncs):
      sortList = None
      for keyFunc in reversed(keyFuncs):
              if sortList is None:
                      sortList = sorted(elements, key = keyFunc)
              else:
                      sortList.sort(key = keyFunc)
      return sortList

It issues this warning:

E1101:  7:radixSort: Instance of 'None' has no 'sort' member