code: def print_msg(contentlist):
          # type: (Union[AnyStr, List[AnyStr], Tuple[AnyStr]]) -> AnyStr
          
          if isinstance(contentlist, list) or isinstance(contentlist, tuple):
              return '\n'.join(contentlist)
          else:  # strings
              if len(contentlist) > 1 and contentlist[-1] != '\n':
                  contentlist += '\n'
              return contentlist
docs: concatenate message list as single string with line feed.