def closing_fence(opener):
    """ Closing pair an an opening fence

    >>> closing_fence('```Python')
    '```'
    """
    if '```' in opener:
        return '```'
    if '~~~' in opener:
        return '~~~'
    if 'highlight' in opener:
        return '{% endhighlight %}'
    if 'syntax' in opener:
        return '{% endsyntax %}'