docs: def help(self):
          """Display command usage information."""
  
          if self.params:
              command = self.params.pop().lstrip('-')
  
              if command in self.command.documentation:
                  (aliases, doc) = self.command.documentation[command]
                  (synopsis, body) = self._split_docstring(doc)
  
                  print(synopsis)
                  if body:
                      print()
                      print(body)
  
              else:
                  raise CommandError('command {0} not known'.format(command))
          else:
              (synopsis, body) = self._split_docstring(__doc__)
  
              print(synopsis)
              print()
              print(body)
              print()
              print('Commands:')
              for command in sorted(self.command.documentation.keys()):
                  print('   ', ', '.join(self.command.documentation[command][0]))
              print()
              print('Use "pymoctool --help COMMAND" for additional '
                    'information about a command.')