The bridge design pattern retrieved from stackoverflow archived documentation

bridge_pattern.py

class Spellbook:
    def cast(self, enemy):
        raise NotImplementedError


class SpellbookFire(Spellbook):
    def cast(self, enemy):
        print("I've lit the {} on fire.".format(enemy))


class SpellbookFreeze(Spellbook):
    def cast(self, enemy):
        print("I've frozen the {}".format(enemy))


class Wizard:
    spellbook = None
    def cast_spell(self, enemy):
        raise NotImplementedError


class BattleWizard(Wizard):
    def __init__(self, spellbook):
        self.spellbook = spellbook

    def cast_spell(self, enemy):
        print ("Yarrrrr!")
        self.spellbook.cast(enemy)


class TimidWizard(Wizard):
    def __init__(self, spellbook):
        self.spellbook = spellbook

    def cast_spell(self, enemy):
        print ("Oh dear!")
        self.spellbook.cast(enemy)


battle_wizard = BattleWizard(SpellbookFire())
timid_wizard = TimidWizard(SpellbookFreeze())

battle_wizard.cast_spell('goblin')   # output: "Yarrrr!"
                                     #         "I've lit the goblin on fire."
timid_wizard.cast_spell('goblin')    # output: "Oh dear!"
                                     #         "I've frozen the goblin."