code: def to_commandline(o):
      
      if isinstance(o, str) and o.startswith("@{") and o.endswith("}"):
          return o
      else:
          return classes.to_commandline(o)
docs: Turns the object into a commandline string. However, first checks whether a string represents
      a internal value placeholder (@{...}).
  
      :param o: the object to turn into commandline
      :type o: object
      :return: the commandline
      :rtype: str