def METHOD_NAME(self, line):
    """
    Process a new line.
    :param line: Line to process
    :type line: bytes
    """
    try:
        key, val = line.split(self._SEPARATOR, 1)
        self._lines[key.decode('utf8').strip()] = val.decode('utf8').strip()
    except ValueError:  # key without a value
        self._lines[line.decode('utf8').strip()] = None