diff --git a/README.md b/README.md
index 7f638f3..8b3fc1b 100644
--- a/README.md
+++ b/README.md
@@ -105,6 +105,7 @@ with gdxpds.gdx.GdxFile() as gdx:
     data = pds.DataFrame([['u' + str(i), i*100] for i in range(1,11)],
                          columns=(gdx[-1].dims + gdx[-1].value_col_names))
     gdx[-1].dataframe = data
+    gdx.write(out_file)
 ```
 
 ## Install