serial-device/command_parser/__init__.py

import re


class CommandParser:
    @staticmethod
    def parse(command_string):

        if not command_string:
            raise ValueError("Empty command received!")

        if not isinstance(command_string, str):
            raise ValueError("Command must be a sting!")

        if re.search('[^a-zA-Z0-9_\-]', command_string):
            raise ValueError('Only [a-zA-Z0-9_\-] allowed')

        if re.search('^GET_.*', command_string):
            parsed_command = command_string.split('_', 1)

            command = parsed_command[0]
            value = parsed_command[1]

            return {'command': command, 'value': value}
        else:
            raise ValueError("Unknown command: " + command_string)