def get_answer(type_: type, placeholder: str=''):
    """Lets user input an answer on a question.
    
    Args:
        type_: Expected answer type to return. 
        placeholder: A placeholder for input() func.
    
    Returns:
        answer(type_): An answer of user.
    
    """
    while True:
        try:
            answer = type_(input(placeholder))
            if isinstance(answer, str):
                answer = answer.lower()
        except ValueError:
            print(f'Use {type_} type for your answer.')
            continue
        return answer