How do you lock a bi-fold door so a 2 year old cant get in?  You search the thingiverse and print what you find.  Duh!!

This is what I found: http://www.thingiverse.com/thing:263534 it was close but not quite right.  The width for the door was too big.  No worries I can re-spin it for my doors an 5 mins of work.

This is what I did:
http://www.thingiverse.com/thing:298054