def env_merge_info(app, env, docnames, other):
    """Standard handler for sphinx's ``env-murge-info`` event. We need to
    implement this because we store data in the build environment, cf.
    ``sphinx.ext.todo``."""
    if not hasattr(other, 'wikisections'):
        return
    if not hasattr(env, 'wikisections'):
        env.wikisections = []
    env.sections += other.sections
