What is the purpose of specifying data types in code using annotations?

In Python, type annotations are used to specify the expected types of variables, function parameters, and return values. This helps to:

• Improve code readability and understanding.
• Allow static analyzers (e.g., mypy) to check type correctness before runtime.
• Facilitate IDE features, providing autocompletion and warnings.

Example:

from typing import List

def greet_all(names: List[str]) -> None:
    for name in names:
        print(f"Hello, {name}!")

Here, it indicates that the function accepts a list of strings and returns nothing. Annotations do not affect code execution; they are meant for tools and developers.