code: def verify_invoice_params(self, price, currency):
      
      if re.match("^[A-Z]{3,3}$", currency) is None:
        raise BitPayArgumentError("Currency is invalid.")
      try: 
        float(price)
      except:
        raise BitPayArgumentError("Price must be formatted as a float")
docs: Deprecated, will be made private in 2.4