docs: public <T> Method getSetMethod(final Object object, final String fieldName, final Class<?> argumentType) {
  		if( object == null ) {
  			throw new NullPointerException("object should not be null");
  		} else if( fieldName == null ) {
  			throw new NullPointerException("fieldName should not be null");
  		} else if( argumentType == null ) {
  			throw new NullPointerException("argumentType should not be null");
  		}
  		
  		Method method = setMethodsCache.get(object.getClass(), argumentType, fieldName);
  		if( method == null ) {
  			method = ReflectionUtils.findSetter(object, fieldName, argumentType);
  			setMethodsCache.set(object.getClass(), argumentType, fieldName, method);
  		}
  		return method;
  	}