docs: def register_module(self, module, url_prefix):
          '''Registers a module with a plugin. Requires a url_prefix that
          will then enable calls to url_for.
  
          :param module: Should be an instance `xbmcswift2.Module`.
          :param url_prefix: A url prefix to use for all module urls,
                             e.g. '/mymodule'
          '''
          module._plugin = self
          module._url_prefix = url_prefix
          for func in module._register_funcs:
              func(self, url_prefix)