<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _touch_checkpoint(self, check_file):
 """ Alternative way for a pipeline to designate a checkpoint. :param str check_file: Name or path of file to use as checkpoint. :return bool: Whether a file was written (equivalent to whether the checkpoint file already existed). :raise ValueError: Raise a ValueError if the argument provided as the checkpoint file is an absolute path and that doesn't correspond to a location within the main output folder. """

        if os.path.isabs(check_file):
            folder, _ = os.path.split(check_file)
            # For raw string comparison, ensure that each path
            # bears the final path separator.
            other_folder = os.path.join(folder, "")
            this_folder = os.path.join(self.outfolder, "")
            if other_folder != this_folder:
                errmsg = "Path provided as checkpoint file isn't in pipeline " \
                         "output folder. '{}' is not in '{}'".format(
                        check_file, self.outfolder)
                raise ValueError(errmsg)
            fpath = check_file
        else:
            fpath = pipeline_filepath(self, filename=check_file)

        # Create/update timestamp for checkpoint, but base return value on
        # whether the action was a simple update or a novel creation.
        already_exists = os.path.isfile(fpath)
        open(fpath, 'w').close()
        action = "Updated" if already_exists else "Created"
        print("{} checkpoint file: '{}'".format(action, fpath))

        return already_exists