code: function( buttonName, buttonLabel, commandName, styleDefiniton ) {
  				// Disable the command if no definition is configured.
  				if ( !styleDefiniton )
  					return;
  
  				var style = new CKEDITOR.style( styleDefiniton ),
  					forms = contentForms[ commandName ];
  
  				// Put the style as the most important form.
  				forms.unshift( style );
  
  				// Listen to contextual style activation.
  				editor.attachStyleStateChange( style, function( state ) {
  					!editor.readOnly && editor.getCommand( commandName ).setState( state );
  				} );
  
  				// Create the command that can be used to apply the style.
  				editor.addCommand( commandName, new CKEDITOR.styleCommand( style, {
  					contentForms: forms
  				} ) );
  
  				// Register the button, if the button plugin is loaded.
  				if ( editor.ui.addButton ) {
  					editor.ui.addButton( buttonName, {
  						label: buttonLabel,
  						command: commandName,
  						toolbar: 'basicstyles,' + ( order += 10 )
  					} );
  				}
  			}
docs: All buttons use the same code to register. So, to avoid duplications, let's use this tool function.