I often wish to perform the action of `subprocess.check_output`, i.e. print
STDOUT live, and check the return code is 0 on exit. However if there is an
error, I would like the STDERR to be printed. When looking at log files and
just seeing the return code is often not very beneficial.
E.g.:
```py
subprocess.check_call(['ping', '-c', '1', 'github.com2'])
```
Will generate this error:
```
subprocess.CalledProcessError: Command '['ping', '-c', '1', 'github.com2']'
returned non-zero exit status 2.
```
Here we are left wondering why it failed, on real world examples it becomes
critical to be able to see what the actual error is. So I find I always have to
wrap such calls in something like this to be able to see STDERR:
```
import subprocess
cmds = ['ping', '-c', '1', 'github.com2']
result = subprocess.run(cmds, stderr=subprocess.PIPE)
if result.returncode != 0:
msg = result.stderr.decode().strip()
raise subprocess.CalledProcessError(f"CALLED SUBPROCESS ERROR: Command: {'
'.join(cmds)}\nReturn code {result.returncode}\nSTDERR: {msg}\n")
```
With the above one gets to see that STDERR is:
```
ping: github.com2: Temporary failure in name resolution
```
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