Python function parameters

Question

While I was reading through a documentation of a library in python,and i came across functions with a weird syntax,like this:
def echo(update: Update, context: CallbackContext):
__some code___

My question is why parameters were written like this,and what are they used for?
Are they default values, or kind of assignment?

Answer 1

ravilnicki
Thanks a million
I appreciate your effort 🙏

Answer 2

ravilnicki
Is it okay if I didn't write them?