if (elem != nullptr && elem->copy_fn != MPI_NULL_COPY_FN) {
ret = elem->copy_fn(this, atoi(key), nullptr, value_in, &value_out, &flag);
if (ret != MPI_SUCCESS) {
if (elem != nullptr && elem->copy_fn != MPI_NULL_COPY_FN) {
ret = elem->copy_fn(this, atoi(key), nullptr, value_in, &value_out, &flag);
if (ret != MPI_SUCCESS) {