Possible mistake in 17- Interfaces vs Types

It says
A class can also implement an interface or a type alias:
class MyCalendar extends MyInterface {}
class MyCalendar extends MyType {}

However, I am under the impression from your tutorial in (16-interfaces) you can only implement an interface?

I had the same question just now - [OOP - Lesson 17] Why is the extends keyword used here?

It’s a shame @Mosh does not really participate in the forums for clarifications.