Technically I don’t think there is a bug. The documentation says [the] “Content-Length header should be explicitly provided”, so if you don’t set it you could argue that you’re using the library wrong.

For this issue I think Demian was trying to add support (i.e. new feature) for implicit Content-Length with tuples and lists of bytes (or strings). He has also added support for iterables of Latin-1 encodable text strings.

What you are suggesting Serhiy sounds like a separate new feature to support bodies of arbitrary bytes-like objects (or lists or tuples of them). According to the documentation, only byte and Latin-1 text strings, file objects supporting stat(), and iterables are currently supported. It does not say, but before this patch I think the iterables had to be of bytes-like objects.