'Strip the trailing router prompt from the output'

def strip_prompt(self, a_string):

    response_list = a_string.split(u'\n')
    new_response_list = []
    for line in response_list:
        if (self.base_prompt not in line):
            new_response_list.append(line)
    output = u'\n'.join(new_response_list)
    return self.strip_context_items(output)
