public FontValue addFont(FontValue value) {
		if (value != null) {
			return fontMap.put(value.getId(), value);
		}
		return null;
	}
Adds the {@link FontValue} to the map. If a FontValue already exists in the map with
the same id, it will be replaced
@param value the {@link FontValue} to store in the map.
@return the previous value for the font key or null if no previous value existed
Ghidra/Framework/Gui/src/main/java/generic/theme/GThemeValueMap.java