docs: def load_plugin_by_name(name):
      """
      Load the plugin with the specified name.
      
      >>> plugin = load_plugin_by_name('default')
      >>> api = dir(plugin)
      >>> 'build_package' in api
      True
      >>> 'get_version' in api
      True
      >>> 'set_package_version' in api
      True
      >>> 'set_version' in api
      True
      """
      plugins = load(PLUGIN_NAMESPACE)
      full_name = "%s.%s" % (PLUGIN_NAMESPACE, name)
      try:
          plugins = (plugin for plugin in plugins if plugin.__name__ == full_name)
          plugin = next(plugins)
          return plugin
      except StopIteration:
          raise UnknownPlugin([plugin.__name__.split('.').pop() for plugin in plugins])