__init__.py 文件源码

def ask(message, options):
    """Ask the message interactively, with the given possible responses"""
    while 1:
        if os.environ.get('PIP_NO_INPUT'):
            raise Exception(
                'No input was expected ($PIP_NO_INPUT set); question: %s' %
                message
            )
        response = input(message)
        response = response.strip().lower()
        if response not in options:
            print(
                'Your response (%r) was not one of the expected responses: '
                '%s' % (response, ', '.join(options))
            )
        else:
            return response