How to use RpcGroup prefix and merge correctly?

export class UserRpcGroup extends RpcGroup.make(
  Rpc.fromTaggedRequest(UserAuthenticatedQuery),
  Rpc.fromTaggedRequest(UserDetailsUpdateMutation),
).prefix('user.') {}

export class DeviceBrandRpcGroup extends RpcGroup.make(
  Rpc.fromTaggedRequest(DeviceBrandCreateMutation),
).prefix('deviceBrand.') {}

export class AppRpcGroup extends RpcGroup.make().merge(
  UserRpcGroup,
  DeviceBrandRpcGroup,
) {}

export class UserRpcGroup extends RpcGroup.make(
  Rpc.fromTaggedRequest(UserAuthenticatedQuery),
  Rpc.fromTaggedRequest(UserDetailsUpdateMutation),
).prefix('user.') {}

export class DeviceBrandRpcGroup extends RpcGroup.make(
  Rpc.fromTaggedRequest(DeviceBrandCreateMutation),
).prefix('deviceBrand.') {}

export class AppRpcGroup extends RpcGroup.make().merge(
  UserRpcGroup,
  DeviceBrandRpcGroup,
) {}

'extends' clause of exported class 'UserRpcGroup' has or is using private name 'RefineSchemaId'.ts(4020)
'extends' clause of exported class 'AppRpcGroup' has or is using private name 'RefineSchemaId'.ts(4020)

'extends' clause of exported class 'UserRpcGroup' has or is using private name 'RefineSchemaId'.ts(4020)
'extends' clause of exported class 'AppRpcGroup' has or is using private name 'RefineSchemaId'.ts(4020)