def update_prompt(self, prompt_text):
if(isinstance(prompt_text, basestring)):<EOL><INDENT>self._prompt = util_functions.sub_chars(prompt_text)<EOL>ret = self._prompt<EOL><DEDENT>else:<EOL><INDENT>raise util_functions.InputError(prompt_text, "<STR_LIT>")<EOL><DEDENT>return ret<EOL>
Update the default prompt string, which is "".
prompt_text should be a string.
Returns the prompt as a confirmation.