docs: protected void _format(SarlBehaviorUnit behaviorUnit, IFormattableDocument document) {
  		formatAnnotations(behaviorUnit, document, XbaseFormatterPreferenceKeys.newLineAfterMethodAnnotations);
  
  		final ISemanticRegionsFinder regionFor = this.textRegionExtensions.regionFor(behaviorUnit);
  
  		document.append(regionFor.keyword(this.keywords.getOnKeyword()), ONE_SPACE);
  
  		if (behaviorUnit.getGuard() != null) {
  			ISemanticRegion keyword = this.textRegionExtensions.immediatelyPreceding(
  					behaviorUnit.getGuard()).keyword(this.keywords.getLeftSquareBracketKeyword());
  			document.prepend(keyword, ONE_SPACE);
  			document.append(keyword, NO_SPACE);
  			keyword = this.textRegionExtensions.immediatelyFollowing(
  					behaviorUnit.getGuard()).keyword(this.keywords.getRightSquareBracketKeyword());
  			document.prepend(keyword, NO_SPACE);
  		}
  
  		document.format(behaviorUnit.getName());
  		document.format(behaviorUnit.getGuard());
  
  		final XExpression expression = behaviorUnit.getExpression();
  		if (expression != null) {
  			final ISemanticRegionFinder finder = this.textRegionExtensions.regionFor(expression);
  			final ISemanticRegion brace = finder.keyword(this.keywords.getLeftCurlyBracketKeyword());
  			document.prepend(brace, XbaseFormatterPreferenceKeys.bracesInNewLine);
  			document.format(expression);
  		}
  	}