code: function updateSiteState( state, siteId, attributes ) {
  	return Object.assign( {}, state, {
  		[ siteId ]: Object.assign( {}, initialSiteState, state[ siteId ], attributes ),
  	} );
  }
docs: Returns a new state with the given attributes updated for the specified site.
  
  @param {Object} state current state
  @param {Number} siteId identifier of the site
  @param {Object} attributes list of attributes and their values
  @returns {Object} the new state