def _check_prompts(pre_prompt, post_prompt):
    '''Check that the prompts are strings'''
    if not isinstance(pre_prompt, str):
        raise TypeError("The pre_prompt was not a string!")
    if post_prompt is not _NO_ARG and not isinstance(post_prompt, str):
        raise TypeError("The post_prompt was given and was not a string!")
Check that the prompts are strings