Session* new_session;
  Status status = NewSession(session_options, &new_session);
  TF_CHECK_OK(status) << status;
  impl_.reset(new Impl(new_session, scope.graph_as_shared_ptr()));
  CHECK_NOTNULL(impl()->session_.get());
}

// Define destructor here so we can forward declare `Impl` in client_session.h.
// If we define a dtor in the header file or use the default dtor,

  bool ok() const;

  // TODO(skyewm): Graph is not part of public API
  Graph* graph() const;

  // TODO(skyewm): Graph is not part of public API
  std::shared_ptr<Graph> graph_as_shared_ptr() const;

  Status status() const;

  /// If status() is ok, convert the Graph object stored in this scope
  /// to a GraphDef proto and return an ok Status. Otherwise, return the error

  }
  return current_constraints;
}

bool Scope::ok() const { return impl()->status_->ok(); }

Graph* Scope::graph() const { return impl()->graph_.get(); }

std::shared_ptr<Graph> Scope::graph_as_shared_ptr() const {
  return impl()->graph_;
}

Status Scope::status() const { return *impl()->status_; }

const std::vector<Operation>& Scope::control_deps() const {
  return impl()->control_deps_;
}