def password_checker() -> str:
    """
    Check password validity.

    The function prompts the user to enter a password and checks if it
    meets a length requirement (at least 8 characters).
    If it does, the function returns the password.
    Otherwise, the user is prompted to enter a new password, until a valid
    password (i.e., at least 8 characters long) is entered.
    Use a while loop and call input('Enter your password: ') each time.
    Every character, including spaces, counts toward the length.

    Returns
    -------
    str
        The valid password.

    Examples
    --------
    >>> password_checker()
    Enter your password: 1234567
    Enter your password: 12345678
    12345678
    """
    raise NotImplementedError("Replace this line with your code.")