docs: def check(self, radl):
          """Check a contextualize."""
  
          if not isinstance(self.max_time, int) or self.max_time < 0:
              raise RADLParseException("Invalid 'max time' in 'contextualize'",
                                       line=self.line)
          if self.items is not None:
              for i in self.items.values():
                  i.check(radl)