def _create_file_if_needed(self):
if not os.path.exists(self._filename):<EOL><INDENT>old_umask = os.umask(<NUM_LIT>)<EOL>try:<EOL><INDENT>open(self._filename, '<STR_LIT>').close()<EOL><DEDENT>finally:<EOL><INDENT>os.umask(old_umask)<EOL><DEDENT><DEDENT>
Create an empty file if necessary.

        This method will not initialize the file. Instead it implements a
        simple version of "touch" to ensure the file has been created.