Enable mode on MRV uses no password.

def enable(self, cmd="enable", pattern=r"#", re_flags=re.IGNORECASE):
        """Enable mode on MRV uses no password."""
        output = ""
        if not self.check_enable_mode():
            self.write_channel(self.normalize_cmd(cmd))
            output += self.read_until_prompt_or_pattern(
                pattern=pattern, re_flags=re_flags
            )
            if not self.check_enable_mode():
                msg = (
                    "Failed to enter enable mode. Please ensure you pass "
                    "the 'secret' argument to ConnectHandler."
                )
                raise ValueError(msg)
        return output