code: def validate_currency(*currencies):
  	
  	validated_currency = []
  	if not currencies:
  		raise CurrencyException('My function need something to run, duh')
  	for currency in currencies:
  		currency = currency.upper()
  		if not isinstance(currency, str):
  			raise TypeError('Currency code should be a string: ' + repr(currency))
  		if currency not in _currencies:
  			raise CurrencyException('Currency code not found: ' + repr(currency))
  		validated_currency.append(currency)
  	return validated_currency[0] if len(validated_currency) == 1 else validated_currency
docs: some validation checks before doing anything