Many programs have their own command subsets, like git (branch, checkout), svn (update, status), and sudo (where any command following sudo is considered a sub-command). sh handles subcommands through attribute access:

from sh import git, sudo

# resolves to "git branch -v"
print(git("branch", "-v")) # the same command

# resolves to "sudo /bin/ls /root"
print(sudo("/bin/ls", "/root")) # the same command

Sub-commands are mainly syntax sugar that makes calling some programs look conceptually nicer.

See also

If you’re using sudo as a subcommand, please be sure to see Using Sudo.