class FTPError(Exception):
	def __init__(self, message="An unknown error occured", code=-1):
		self.message = message
		self.code = code
		super().__init__(self.message)

def parse_ftp_command(cmd):
	tokens = cmd.split(" ")

	if len(tokens) == 0:
		raise FTPError("No command issued!")

	command_name = tokens[0].upper()
	arguments = tokens[1:]

	return (command_name, arguments)

def get_argument(args, name, index):
	try:
		return args[index]
	except IndexError:
		raise FTPError(f"Missing argument '{name}'", 2138)