code: def isset(name):
      
      def wrapped(func):
          @functools.wraps(func)
          def _decorator(*args, **kwargs):
              if core.isset(name):
                  return func(*args, **kwargs)
          return _decorator
      return wrapped
docs: Only execute the function if the variable is set.
  
      Args:
          name: The name of the environment variable
  
      Returns:
          The function return value or `None` if the function was skipped.