def load_backends_and_plugins(plugins, working_set, backends, build_configuration=None):
  """Load named plugins and source backends

  :param list<str> plugins: Plugins to load (see `load_plugins`).  Plugins are loaded after
    backends.
  :param WorkingSet working_set: A pkg_resources.WorkingSet to load plugins from.
  :param list<str> backends: Source backends to load (see `load_build_configuration_from_source`).
  """
  build_configuration = build_configuration or BuildConfiguration()
  load_build_configuration_from_source(build_configuration, backends)
  load_plugins(build_configuration, plugins or [], working_set)
  return build_configuration
Load named plugins and source backends

  :param list<str> plugins: Plugins to load (see `load_plugins`).  Plugins are loaded after
    backends.
  :param WorkingSet working_set: A pkg_resources.WorkingSet to load plugins from.
  :param list<str> backends: Source backends to load (see `load_build_configuration_from_source`).