code: public static void registerTypeConversion(Conversion<?> conversion) {
  
  		Object[] keys=conversion.getTypeKeys();
  		if (keys==null) {
  			return;
  		}
  
  		for (int i=0; i<keys.length; i++) {
  			registerTypeConversion(keys[i],conversion);
  		}
  	}
docs: Register a type conversion object under the specified keys. This
  method can be used by developers to register custom type conversion
  objects.