code: function( ids ) {
  		var promises = [],
  			i = 0
  		;
  
  		if( !Array.isArray( ids ) )
  			ids = [ ids ];
  
  		for(; i<ids.length; i++ ){
  			if( this._promises[ ids[i] ] )
  				promises.push( this._promises[ ids[i] ] );
  		}
  
  		if( !promises.length )
  			return this._Promise.resolve();
  
  		return this._Promise.all( promises );
  	}
docs: Creates a promise and waits for the callbacks specified to complete before resolve it.
  If it is used by an actionCallback, the promise should be resolved to let other callbacks
  wait for it if needed.
  
  Be careful of not to wait by a callback that is waiting by the current callback, or the
  promises will never fulfill.
  
  @param  {String<Array>|String} ids The id or ids of the callbacks/stores to wait for.
  @return {Promise} A promise to be resolved when the specified callbacks are completed.