Object

Ensure that variable is an object. Associative array will be transformed automatcially to stdClass.

Correct:

assure($x = new stdClass, 'object');
assure($x = new SomeObject, 'object');
assure($x = ['x'=> 10, 'y'=20], 'object');

Incorect:

assure($x = 1, 'object');
assure($x = false, 'object');
assure($x = true, 'object');
assure($x = '', 'object');
assure($x = [], 'object');

All above values will throw \InvalidArgumentException