diff --git a/internal/ceres/graph.h b/internal/ceres/graph.h
index 9b26158..4f8dfb9 100644
--- a/internal/ceres/graph.h
+++ b/internal/ceres/graph.h
@@ -1,5 +1,5 @@
 // Ceres Solver - A fast non-linear least squares minimizer
-// Copyright 2015 Google Inc. All rights reserved.
+// Copyright 2023 Google Inc. All rights reserved.
 // http://ceres-solver.org/
 //
 // Redistribution and use in source and binary forms, with or without
@@ -36,21 +36,19 @@
 #include <unordered_set>
 #include <utility>
 
+#include "ceres/internal/export.h"
 #include "ceres/map_util.h"
 #include "ceres/pair_hash.h"
 #include "ceres/types.h"
 #include "glog/logging.h"
 
-namespace ceres {
-namespace internal {
+namespace ceres::internal {
 
 // A unweighted undirected graph templated over the vertex ids. Vertex
 // should be hashable.
 template <typename Vertex>
-class Graph {
+class CERES_NO_EXPORT Graph {
  public:
-  Graph() {}
-
   // Add a vertex.
   void AddVertex(const Vertex& vertex) {
     if (vertices_.insert(vertex).second) {
@@ -106,8 +104,6 @@
 template <typename Vertex>
 class WeightedGraph {
  public:
-  WeightedGraph() {}
-
   // Add a weighted vertex. If the vertex already exists in the graph,
   // its weight is set to the new weight.
   void AddVertex(const Vertex& vertex, double weight) {
@@ -209,7 +205,6 @@
       edge_weights_;
 };
 
-}  // namespace internal
-}  // namespace ceres
+}  // namespace ceres::internal
 
 #endif  // CERES_INTERNAL_GRAPH_H_