code: public final Set<String> getAsHTMLClassSet() {
  		Set<String> htmlClasses = new HashSet<>();
  		final String htmlClassPrefix = "wc-margin-";
  		final String topClassModifier = "n-";
  		final String rightClassModifier = "e-";
  		final String bottomClassModifier = "s-";
  		final String leftClassModifier = "w-";
  
  		Size current = getTop();
  		if (current != null) {
  			htmlClasses.add(htmlClassPrefix.concat(topClassModifier).concat(current.toString()));
  		}
  		current = getRight();
  		if (current != null) {
  			htmlClasses.add(htmlClassPrefix.concat(rightClassModifier).concat(current.toString()));
  		}
  		current = getBottom();
  		if (current != null) {
  			htmlClasses.add(htmlClassPrefix.concat(bottomClassModifier).concat(current.toString()));
  		}
  		current = getLeft();
  		if (current != null) {
  			htmlClasses.add(htmlClassPrefix.concat(leftClassModifier).concat(current.toString()));
  		}
  
  		if (htmlClasses.isEmpty()) {
  			return null;
  		}
  		return htmlClasses;
  	}
docs: Get a set of HTML class attribute values in the same form as {@link AbstractWComponent#getHtmlClasses}.
  
  @return the Margin expressed as a set of HTML class attribute values.