problem in using subprocess module

[akbarza]

hi
when i was reading the page https://realpython.com/python-eval-funct...es-of-eval about eval() in python, i encounterd a problem.
in the code (the below code is on the above page):

# Run the echo command
import subprocess
eval("subprocess.getoutput('echo Hello, World')")

# Launch Firefox (if available)
eval("subprocess.getoutput('firefox')")

when I ran it, I took the below :

Error:
"'firefox' is not recognized as an internal or external command,\noperable program or batch file."

I think the code is used for running Firefox from inside Python. is it true?
why did not the code run successfully?
I have another question:
is it possible to take information about something in Python? For example, suppose I want to know about %
usage in Python. when I am in idle , I wrote help(%), and it takes an error as

Error:
SyntaxError: invalid syntax

. how can I take information about something in idle?
thanks