def can_vote(age: int) -> bool:
    """Return True iff age is legal voting age of at least 18 years.

    >>> can_vote(16)
    False
    >>> can_vote(21)
    True
    """
    
    if age < 18:
        return False
    else:
        return True


def is_teenager(age: int) -> bool:
    """Return True iff age is a teenager between 13 and 18 inclusive.

    >>> is_teenager(4)
    False
    >>> is_teenager(16)
    True
    >>> is_teenager(19)
    False
    """
    
    if age < 13:
        return False
    else:
        if age > 18:
            return False
        else:
            return True