@staticmethod<EOL><INDENT>def __get_checksum(byte_str):<DEDENT>
return sum(byte2int(x) for x in byte_str[:-<NUM_LIT:1>]) % <NUM_LIT><EOL>
Calculates checksum of string, excluding last character.
Checksum is generated by summing all byte values, except last,
and taking lowest byte of result.

:param byte_str: string to checksum, plus extra character on end
:return: checksum value as int