if ( search( refHead, val, pos, key_comparator() ) ) {
assert( key_comparator()( val, *node_traits::to_value_ptr( *pos.pCur ) ) == 0 );
if ( search( refHead, val, pos, key_comparator() ) ) {
assert( key_comparator()( val, *node_traits::to_value_ptr( *pos.pCur ) ) == 0 );