from typing import Dict
from typing import Any


def key_is_true(dct: Dict[str, Any], key: str) -> bool:
    """
    Check if a dictionary contains a key who's value is set to True.
    Truthy values should return False.

    >>> key_is_true({'a': True}, 'a')
    True

    >>> key_is_true({'a': False}, 'a')
    False

    >>> key_is_true({'a': True}, 'b')
    False

    >>> key_is_true({'a': "True"}, 'a')
    False
    """
    return key in dct and dct[key] is True