Fix error message about non-existent _static path
diff --git a/doc/conf.py b/doc/conf.py
index 16289bb..b13925f 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -123,7 +123,7 @@
# Add any paths that contain custom static files (such as style sheets) here,
# relative to this directory. They are copied after the builtin static files,
# so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = ['_static']
+# html_static_path = ['_static']
# If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
# using the given strftime format.