dwa_1073_command_pattern.py

# Receiver
class Volume:
	def __init__(self, volume=0):
		self.volume = volume

	def volume_up(self, value=1):
		self.volume += value
		print(f"Volume is Up - {self.volume}")

	def volume_down(self, value=1):
		self.volume -= value
		print(f"Volume is Down - {self.volume}")

# Invoker
class Remote:
	def __init__(self):
		self.commands = {}

	def register(self, command_name, command):
		self.commands[command_name] = command

	def execute(self, command_name):
		if self.commands.get(command_name):
			command = self.commands.get(command_name)
			command.execute()
		else:
			print(f"Command {command_name} is not recognized")

from abc import abstractmethod, ABCMeta
class IVolume(metaclass=ABCMeta):

	@abstractmethod
	def execute(self):
		pass

class VolumeUpCommand(IVolume):
	def __init__(self, volume):
		self.volume = volume

	def execute(self):
		self.volume.volume_up()

class VolumeDownCommand(IVolume):
	def __init__(self, volume):
		self.volume = volume

	def execute(self):
		self.volume.volume_down()

# Create a receiver
volume = Volume()

# Commands
volume_up_cmd = VolumeUpCommand(volume=volume)
volume_down_cmd = VolumeDownCommand(volume=volume)

# Register the command in Remote(Invoker)
remote = Remote()
remote.register("+", volume_up_cmd)
remote.register("-", volume_down_cmd)

remote.execute("+")
remote.execute("+")
remote.execute("-")
remote.execute("+")