diff --git a/demo.py b/demo.py
index 9ec21be..3e3cb3a 100644
--- a/demo.py
+++ b/demo.py
@@ -13,6 +13,10 @@
 
 from docopt import docopt
 opt = docopt(__doc__)
-print(opt["--arg4"])
-print(opt)
-print(type(opt))
+def main(arg4):
+  print(arg4)
+  print(opt)
+  print(type(opt))
+
+if __name__ == "__main__":
+  main(opt["--arg4"])