How to Specify Return Types in Python?

Python is a dynamically typed language, which means that it infers the type of a variable at runtime rather than at compile-time. As such, it doesn’t have explicit syntax for specifying the return type of a function or method.

However, you can use type annotations in Python 3 to specify the expected types of the input arguments and return value of a function or method. Here’s an example:

def add_numbers(x: int, y: int) -> int:
    return x + y

In this example, we define a function called add_numbers that takes two integers as input arguments and returns an integer. The types of the input arguments and return value are specified using type annotations.

Type annotations do not affect the behavior of the Python interpreter in any way. They are used primarily for documentation purposes and to help catch type-related errors during development.

You can also use external libraries like mypy to enforce type checking based on type annotations. mypy is a static type checker for Python that can help you catch type-related errors at compile-time rather than runtime.

Note that while type annotations can help make your code more readable and maintainable, they are not strictly necessary in Python. You can still write fully functional Python code without using any type annotations.