code: function( tagName, rules )
  			{
  				var currentRules = this._.rules[ tagName ];
  
  				if ( currentRules )
  					CKEDITOR.tools.extend( currentRules, rules, true );
  				else
  					this._.rules[ tagName ] = rules;
  			}
docs: Sets formatting rules for a given tag. The possible rules are:
  <ul>
  <li><b>breakBeforeOpen</b>: break line before the opener tag for this element.</li>
  <li><b>breakAfterOpen</b>: break line after the opener tag for this element.</li>
  <li><b>breakBeforeClose</b>: break line before the closer tag for this element.</li>
  <li><b>breakAfterClose</b>: break line after the closer tag for this element.</li>
  </ul>
  
  All rules default to "false". Each call to the function overrides
  already present rules, leaving the undefined untouched.
  
  @param {String} tagName The tag name to which set the rules.
  @param {Object} rules An object containing the element rules.
  @example
  // Break line before and after "img" tags.
  writer.setRules( 'list',
  {
  breakBeforeOpen : true
  breakAfterOpen : true
  });