# Reserved Method Names

As you may have noticed, Mockery uses a number of methods called directly on all mock objects, for example `shouldReceive()`. Such methods are necessary in order to setup expectations on the given mock, and so they cannot be implemented on the classes or objects being mocked without creating a method name collision (reported as a PHP fatal error). The methods reserved by Mockery are:

- `shouldReceive()`
- `shouldBeStrict()`

In addition, all mocks utilise a set of added methods and protected properties which cannot exist on the class or object being mocked. These are far less likely to cause collisions. All properties are prefixed with `_mockery` and all method names with `mockery_`.