code: function( forms ) {
  			if ( this.disabled )
  				return;
  
  			if ( !forms )
  				return;
  
  			var i, form,
  				transfGroups = [],
  				preferredForm;
  
  			// First, find preferred form - this is, first allowed.
  			for ( i = 0; i < forms.length && !preferredForm; ++i ) {
  				form = forms[ i ];
  
  				// Check only strings and styles - array format isn't supported by #check().
  				if ( ( typeof form == 'string' || form instanceof CKEDITOR.style ) && this.check( form ) )
  					preferredForm = form;
  			}
  
  			// This feature doesn't have preferredForm, so ignore it.
  			if ( !preferredForm )
  				return;
  
  			for ( i = 0; i < forms.length; ++i )
  				transfGroups.push( getContentFormTransformationGroup( forms[ i ], preferredForm ) );
  
  			this.addTransformations( transfGroups );
  		}
docs: Adds an array of {@link CKEDITOR.feature} content forms. All forms
  will then be transformed to the first form which is allowed by the filter.
  
  editor.filter.allow( 'i; span{!font-style}' );
  editor.filter.addContentForms( [
  'em',
  'i',
  [ 'span', function( el ) {
  return el.styles[ 'font-style' ] == 'italic';
  } ]
  ] );
  // Now <em> and <span style="font-style:italic"> will be replaced with <i>
  // because this is the first allowed form.
  // <span> is allowed too, but it is the last form and
  // additionaly, the editor cannot transform an element based on
  // the array+function form).
  
  This method is used by the editor to register {@link CKEDITOR.feature#contentForms}
  when adding a feature with {@link #addFeature} or {@link CKEDITOR.editor#addFeature}.
  
  @param {Array} forms The content forms of a feature.