I was trying to figure out why asyncio.Stream.write accepts a str as a buffer (hoping this is the correct category). It looks like a str can be appended to a bytes:

>>> b'foo' + 'bar'
b'foobar'

The converse however is not true:

>>> 'bar' + b'foo'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unsupported types for __add__: 'str', 'bytes'

(at least on the unix port).

Does asyncio.Stream.write officially support str? And is + : bytes -> str -> bytes expected?