// the device is not usable. In case of a bad status, `device.delete_device` is
// still called on `device_info` (i.e. the caller does not retain ownership).
//
// This API is highly experimental, and in particular is expected to change when
// it starts supporting operations with attributes and when tf.function support
// is added.
TF_CAPI_EXPORT extern void TFE_RegisterCustomDevice(TFE_Context* ctx,

            break;
          }
        }
        if (!found) {
          return errors::Internal(
              "Internal state of the gradient tape is invalid: "
              "none of operations outputs match expected tensor");
        }
      } else {
        // This target tensor was not generated by any operation recorded on
        // the tape, so no gradient needs to be computed from it unless this