ExitStatus.code
Returns the exit code of the process, if any.
In Unix terms the return value is the exit status: the value passed to
exit, if the
process finished by calling exit. Note that on Unix the exit status is truncated to 8
bits, and that values that didn’t come from a program’s call to exit may be invented by the
runtime system (often, for example, 255, 254, 127 or 126).
On Unix, this will return None if the process was terminated by a signal.
ExitStatus.signal
If the process was terminated by a signal, returns that signal.
In other words, if
WIFSIGNALED, this returns WTERMSIG.
Avability: UNIX
ExitStatus.stopped_signal
If the process was stopped by a signal, returns that signal.
In other words, if
WIFSTOPPED, this returns WSTOPSIG. This is only possible if the status came from
a wait system call which was passed WUNTRACED, and was then converted into an ExitStatus.
Avability: UNIX
ExitStatus.success
Was termination successful? Signal termination is not considered a success, and success is defined as a zero exit status.

