What is a function signature?

Question

I was studying python and I ran into the concept of 'signature'. I looked things up but signature of a function seems to have different meaning for different languages. So, what does signature of a function refer to in python?

Answer 1

In general the signature of a function is defined by the number and type of input arguments the function takes and the type of the result the function returns.

As an example in C++ consider the following function:

int multiply(int x, int y){
    return x*y;
}

The signature of that function, described in an abstract way would be the set {int, int, int}.

As Python is a weakly typed language in general the signature is only given by the amount of parameters. But in newer Python versions type hints were introduced which clarify the signature:

def multiply(x: int, y: int) -> int:
    return x*y