Availability:built-in
dict_same_keys(?Dict1, 
?Dict2)True when Dict1 and Dict2 have the same set of 
keys. The
tag is not considered. This predicate is semidet if both 
arguments are instantiated to a dict. If one is instantiated to a dict 
and the other is unbound, it generates a dict with the same keys and 
unbound tag and values. The predicate is_dict/2 
may be used test tag equivalence or unify the tags. This predicate 
raises an instantiation_error if both argument are unbound 
or a type_error if one of the arguments is neither a dict 
nor a variable.