Process ``Molfile``.
    
    :param stream: Queue containing lines of text.
    :type stream: :py:class:`collections.deque`
    :return: Tuples of data.

def _molfile(stream):
    """Process ``Molfile``.
    
    :param stream: Queue containing lines of text.
    :type stream: :py:class:`collections.deque`
    :return: Tuples of data.
    """
    yield MolfileStart()
    yield HeaderBlock(stream.popleft().strip(), stream.popleft().strip(), stream.popleft().strip())
    # yield from _ctab(stream)
    for token in _ctab(stream):
        yield token
    yield MolfileEnd()