// Returns whether `device_name` is registered as a custom device.
  virtual bool IsCustomDevice(const string& device_name) = 0;

  // Register a custom device. It will return error is the device name is
  // already registered.
  // TODO(tfrt-devs): Remove this method. Let caller register it directly into
  // CustomDeviceOpHandler.
  virtual Status RegisterCustomDevice(const string& name,

TF_CAPI_EXPORT extern void TF_DeletePluggableDeviceLibraryHandle(
    TF_Library* lib_handle);

// Removes `func_name` from `g`. If `func_name` is not in `g`, an error will be
// returned.
TF_CAPI_EXPORT extern void TF_GraphRemoveFunction(TF_Graph* g,
                                                  const char* func_name,
                                                  TF_Status* status);

#ifdef __cplusplus
} /* end extern "C" */

        out_gradients.push_back(nullptr);
        if (build_default_zeros_grads) {
          auto func_name_it =
              FunctionsAcceptingNoneForIndicesMap()->find(trace.op_type);
          if (func_name_it == FunctionsAcceptingNoneForIndicesMap()->end() ||
              func_name_it->second.find(i) == func_name_it->second.end()) {
            zero_indices.push_back(i);
          }
        }
      } else {

TF_CAPI_EXPORT extern TF_AttrType TFE_OpNameGetAttrType(
    TFE_Context* ctx, const char* op_or_function_name, const char* attr_name,
    unsigned char* is_list, TF_Status* status);

TF_CAPI_EXPORT extern void TFE_OpSetAttrString(TFE_Op* op,
                                               const char* attr_name,
                                               const void* value,
                                               size_t length);

  ///
  /// DEFAULT IMPLEMENTATION: Uses `io::CleanPath` and `io::ParseURI`.
  char* (*translate_name)(const TF_Filesystem* filesystem, const char* uri);

  /// Finds all entries in the directory given by `path`.
  ///
  /// The returned entries are paths relative to `path`.
  ///
  /// Plugins must allocate `entries` to hold all names that need to be returned
  /// and return the size of `entries`. Caller takes ownership of `entries`