code: function getAttachment( val, valType, onFound, onNotFound ) {
  		var requestData;
  
  		if ( ! val ) {
  			onNotFound();
  			return;
  		}
  
  		if ( 'url' === valType ) {
  			requestData = {
  				action: 'get-attachment-by-url',
  				url: val
  			};
  		} else {
  			requestData = {
  				action: 'get-attachment',
  				id: parseInt( val, 10 )
  			};
  		}
  
  		wp.media.ajax({
  			type: 'POST',
  			data: requestData,
  			success: onFound,
  			error: onNotFound
  		});
  	}
docs: Gets an attachment object via AJAX based on a given ID or URL.
  
  @since 0.7.0
  
  @private
  
  @param {number|string} val        Attachment ID or URL.
  @param {string}        valType    Whether 'val' was provided as 'id' or 'url'.
  @param {function}      onFound    Callback to pass the found attachment to.
  @param {function}      onNotFound Callback to run if no attachment was found.
  
  @return {void}