<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def delete_user(self, api_token, password, **kwargs):
 """Delete a registered Todoist user's account. :param api_token: The user's login api_token. :type api_token: str :param password: The user's password. :type password: str :param reason_for_delete: The reason for deletion. :type reason_for_delete: str :param in_background: If ``0``, delete the user instantly. :type in_background: int :return: The HTTP response to the request. :rtype: :class:`requests.Response` """

        params = {
            'token': api_token,
            'current_password': password
        }
        return self._post('delete_user', params, **kwargs)