code: function getQueryManager( state, siteId ) {
  	if ( ! siteId ) {
  		return state.posts.allSitesQueries;
  	}
  	return state.posts.queries[ siteId ] || null;
  }
docs: Returns the PostsQueryManager from the state tree for a given site ID (or
  for queries related to all sites at once).
  
  @param  {Object}  state  Global state tree
  @param  {?Number} siteId Site ID, or `null` for all-sites queries
  @return {Object}         Posts query manager