For each element in the AArray, call dg(Key* pkey, Value* pvalue) If dg returns !=0, stop and return that value.
delegate to call for each key/value pair
!=0 : value returned by first dg() call that returned non-zero 0 : no entries in aa, or all dg() calls returned 0
See Implementation
For each element in the AArray, call dg(Key* pkey, Value* pvalue) If dg returns !=0, stop and return that value.