code: def _is_junction(arg):
      '''
      Return True, if arg is a junction statement.
      '''
      return isinstance(arg, dict) and len(arg) == 1 and next(six.iterkeys(arg)) == 'junctionf _is_junction(arg):
      '''
      Return True, if arg is a junction statement.
      '''
      return isinstance(arg, dict) and len(arg) == 1 and next(six.iterkeys(arg)) == 'junction'
docs: Return True, if arg is a junction statement.