import string


def header_link(title):
    """Return a github-style link target for a title.

    >>> header_link('Hello there!')
    'hello-there'
    """
    # This doesn't handle multiple titles with the same text in the
    # same file, but usually that's not a problem. GitHub makes
    # links like the-title, the-title-1, the-title-2 etc.
    result = ''
    for character in title:
        if character in string.whitespace:
            result += '-'
        elif character in string.punctuation:
            pass
        else:
            result += character.lower()
    return result