"foo=bar=bat" parsed incorrectly

[egnor]

% python
Python 3.9.5 (default, May 11 2021, 08:20:37) 
[GCC 10.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import logfmt.parser
>>> logfmt.parser.parse_line("foo=bar=bat")
{'foo': 'bar', 'bat': True}

By my reading of https://pkg.go.dev/github.com/kr/logfmt, this should be {'foo': 'bar=bat'}, since string_byte includes = (though ident_byte does not).