'Attempts to return the URL of the apple-touch-icon of the most
preferred size (based on the order in cls._appletouchicon_sizes). If
one is not defined, returns None.'

def _check_apple_icon(self):

    for size in self._appletouchicon_sizes:
        icon = self._check_apple_icon_size(size)
        if icon:
            return icon
    return None
