QuickBooks/Callbacks.php
static protected function _callObjectMethod($object_and_method, &$vars, &$err, $which = null)
	{
		$object = current($object_and_method);
		$method = next($object_and_method);

		if (is_callable(array( $object, $method)))
		{
			$ret = call_user_func_array( array( $object, $method ), $vars);

			if (!is_null($which))
			{
				$err = $vars[$which];
			}

			return $ret;
		}

		$err = 'Object method does not exist: instance of ' . get_class($object) . '->' . $method . '(...)';
		return false;
	}
static protected function _callObjectMethod($object_and_method, &$vars, &$err, $which = null)
	{
		$object = current($object_and_method);
		$method = next($object_and_method);

		if (is_callable(array( $object, $method)))
		{
			$ret = call_user_func_array( array( $object, $method ), $vars);

			if (!is_null($which))
			{
				$err = $vars[$which];
			}

			return $ret;
		}

		$err = 'Object method does not exist: instance of ' . get_class($object) . '->' . $method . '(...)';
		return false;
	}
Call an object method callback (object instance method)

@param array $object_and_method		An array with two indexes: array( 0 => $object_instance, 1 => 'method_to_call' )
@param array $vars
@param string $err
@param integer $which
@return mixed