How to use the pyrfc.CommunicationError function in pyrfc

field_widths = [20, 17, 10, 10, 9, 9, 10, 15]

                sys.stdout.write(u" " * 4 + u"-----------( Structure of {0.name} (n/uc_length={0.nuc_length}/{0.uc_length})--\n".format(type_desc))
                for key, width in zip(field_keys, field_widths):
                    sys.stdout.write(u"{0}".format(key).ljust(width).upper() + u" ")
                sys.stdout.write(u"\n")

                for field_description in type_desc.fields:
                    for key, width in zip(field_keys, field_widths):
                        sys.stdout.write(u"{0}".format(field_description[key]).ljust(width) + u" ")
                    sys.stdout.write(u"\n")
                sys.stdout.write(u" " * 4 + u"-----------( Structure of {0.name} )-----------\n".format(type_desc))
            sys.stdout.write(u"-" * sum(parameter_widths) + u"\n")
        connection.close()

    except CommunicationError:
        print ("Could not connect to server.")
        raise
    except LogonError:
        print ("Could not log in. Wrong credentials?")
        raise
    except (ABAPApplicationError, ABAPRuntimeError):
        print ("An error occurred.")
        raise