This might be a good explanation for this behavior: http://stackoverflow.com/questions/2858603/why-is-keyword-has-different-behavior-when-there-is-dot-in-the-s

This might be a good explanation for this behavior: http://stackoverflow.com/questions/2858603/why-is-keyword-has-different-behavior-when-there-is-dot-in-the-string http://stackoverflow.com/questions/2858603/why-is-keyword-ha... tl;dr; use "is" only with singetons (None etc)