Do Decorators in Python necessarily implement the Decorator Pattern?

In Python,

1. Is it correct that decorators in Python can change the interface of the decorated function/class, e.g. change the signature of the decorated functions and methods of decorated class? For example:

   >>> def MyDecorator(func):
   ...     def NewFunc():
   ...         pass
   ...     return NewFunc
   ... 
   >>> @MyDecorator
   ... def MyFunc(a, b, c):
   ...     print(a,b,c)
   ...
   
   

2. So decorators in Python are not necessarily used for implementing the decorator design pattern as described in the book "Design Pattern" by GoF?

3. Is it a bad practice to write a decorator which change the interface of the decorated function/class?

Thanks.