Python isinstance checks behave differently from type annotations

integer_float.py

>>> isinstance(1, int)
True  # 👍

>>> isinstance(1, float)
False  # 👍

>>> isinstance(1.0, int)
False  # 👍

>>> isinstance(1.0, float)
True  # 👍


def integer_integer() -> int:
    return 1  # 👍


def integer_float() -> float:
    return 1  # ❌ no complaint from mypy for returning an integer with float annotation


def float_integer() -> int:
    return 1.0  # 👍 mypy complains


def float_float() -> float:
    return 1.0  # 👍