code: def setDerivedTypeContents(self, extensions=None, restrictions=None):
          
          if extensions:
              ofwhat = list(self.ofwhat)
              if type(extensions) in _seqtypes:
                  ofwhat += list(extensions)
              else:
                  ofwhat.append(extensions)
          elif restrictions:
              if type(restrictions) in _seqtypes:
                  ofwhat = restrictions
              else:
                  ofwhat = (restrictions,)
          else:
              return
          self.ofwhat = tuple(ofwhat)
          self.lenofwhat = len(self.ofwhat)
docs: For derived types set appropriate parameter and