@register.tag
def get_rotating_photo(parser, token):
    """Pick at random a photo from a given photologue gallery and return the img tag to display it.

    Takes 3 args:
    - the gallery to pick a photo from. This can be either the slug of a gallery, or a variable that holds either a
      gallery instance or a gallery slug.
    - the photosize to use.
    - a CSS class to apply to the img tag.
    """
    try:
        # Split the contents of the tag, i.e. tag name + argument.
        tag_name, gallery, photosize, css_class = token.split_contents()
    except __HOLE__:
        msg = '%r tag requires 3 arguments' % token.contents[0]
        raise template.TemplateSyntaxError(msg)
    return PhotoGalleryNode(gallery, photosize[1:-1], css_class[1:-1])
dataset/ETHPy150Open jdriscoll/django-photologue/photologue/templatetags/photologue_tags.py/get_rotating_photo