class Printer:

$"""$A Printer.

Attributes:

$-$ message: the message to print

$"""$

message: str

def $\_\_$init$\_\_($self$,$ message: str$)->$ None:

self.message $=$ message

def print$\_$message$($self$)$:

$"""$Prints a message.

$"""$

print$($self$.$message$)$

class MysteryPrinter$($Printer$)$:

def $\_\_$init$\_\_($self$,$ message: str$)->$ None:

Printer.$\_\_$init$\_\_($self$,$ message $+$ message$)$

class DoublePrinter$($MysteryPrinter$)$:

def print$\_$message$($self$)$:

print$($self$.$message $+$ self.message$)$

if $\_\_$name$\_\_==\text{'}\_\_$main$\_\_\text{'}$:

m$1=$ Printer$(\text{'}$hello$\text{'})$

m$2=$ MysteryPrinter$(\text{'}$good$\text{'})$

m$3=$ DoublePrinter$(\text{'}$bye$\text{'})$

m$1.$print$\_$message$()$ # Line $1$

m$2.$print$\_$message$()$ # Line $2$

m$3.$print$\_$message$()$ # Line $3$