Looks like python needs eof() or something for file objects, just like
any other languages.

Since read() is using the system call, that's the right behavior: read()
blocks until EOF, and returns whatever was buffered. EOF character is
consumed, but since it's a stdin, it is never closed. The next read()
will again wait for normal input.

The 2nd EOF mark without anything in-between will return an empty string.