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