Retrieve the ``__version__`` attribute for Layabout.

def get_version(string):
    """ Retrieve the ``__version__`` attribute for Layabout. """
    flags = re.S
    pattern = r".*__version__ = '(.*?)'"
    match = re.match(pattern=pattern, string=string, flags=flags)

    if match:
        return match.group(1)

    raise RuntimeError('No version string could be matched')