diff --git a/sshuttle/cmdline.py b/sshuttle/cmdline.py
index ab45378..94ee582 100644
--- a/sshuttle/cmdline.py
+++ b/sshuttle/cmdline.py
@@ -38,6 +38,8 @@ def main():
     helpers.verbose = opt.verbose
 
     try:
+        # Since namespace and namespace-pid options are only available
+        # in linux, we must check if it exists with getattr
         namespace = getattr(opt, 'namespace', None)
         namespace_pid = getattr(opt, 'namespace_pid', None)
         if namespace or namespace_pid: