'\'start_response()\' callable as specified by PEP 333'

def start_response(self, status, headers, exc_info=None):

    if exc_info:
        try:
            if self.headers_sent:
                raise exc_info[0], exc_info[1], exc_info[2]
        finally:
            exc_info = None
    elif (self.headers is not None):
        raise AssertionError('Headers    already    set!')
    self.status = status
    self.headers = self.headers_class(headers)
    return self.write
