Availability:built-in
get_dict(?Key, 
+Dict, -Value)Unify the value associated with Key in dict with Value. 
If
Key is unbound, all associations in Dict are 
returned on backtracking. The order in which the associations are 
returned is undefined. This predicate is normally accessed using the 
functional notation Dict.Key. See section 
5.4.1.
Fails silently if Key does not appear in Dict. This is different from 
the behavior of the functional‘.`-notation, which throws an 
existence error in that case.