Error CS1061 unity how to fix the error (Blockchain Game using Moralis, Unity, C#)?

The second part of the code(189-326):

void StoreNavMeshDataIfInPrefab(NavMeshSurface surfaceToStore)
        {
            var prefabStage = PrefabStageUtility.GetPrefabStage(surfaceToStore.gameObject);
            var isPartOfPrefab = prefabStage != null && prefabStage.IsPartOfPrefabContents(surfaceToStore.gameObject);
            if (!isPartOfPrefab)
                return;

            // check if data has already been stored for this surface
            foreach (var storedAssetInfo in m_PrefabNavMeshDataAssets)
                if (storedAssetInfo.Surface == surfaceToStore)
                    return;

            if (m_PrefabNavMeshDataAssets.Count == 0)
            {
                PrefabStage.prefabSaving -= DeleteStoredNavMeshDataAssetsForOwnedSurfaces;
                PrefabStage.prefabSaving += DeleteStoredNavMeshDataAssetsForOwnedSurfaces;

                PrefabStage.prefabStageClosing -= ForgetUnsavedNavMeshDataChanges;
                PrefabStage.prefabStageClosing += ForgetUnsavedNavMeshDataChanges;
            }

            var isDataOwner = true;
            if (PrefabUtility.IsPartOfPrefabInstance(surfaceToStore) && !PrefabUtility.IsPartOfModelPrefab(surfaceToStore))
            {
                var basePrefabSurface = PrefabUtility.GetCorrespondingObjectFromSource(surfaceToStore) as NavMeshSurface;
                isDataOwner = basePrefabSurface == null || surfaceToStore.navMeshData != basePrefabSurface.navMeshData;
            }
            m_PrefabNavMeshDataAssets.Add(new SavedPrefabNavMeshData { Surface = surfaceToStore, NavMeshData = isDataOwner ? surfaceToStore.navMeshData : null });
        }

        bool IsCurrentPrefabNavMeshDataStored(NavMeshSurface surface)
        {
            if (surface == null)
                return false;

            foreach (var storedAssetInfo in m_PrefabNavMeshDataAssets)
            {
                if (storedAssetInfo.Surface == surface)
                    return storedAssetInfo.NavMeshData == surface.navMeshData;
            }

            return false;
        }

        void DeleteStoredNavMeshDataAssetsForOwnedSurfaces(GameObject gameObjectInPrefab)
        {
            // Debug.LogFormat("DeleteStoredNavMeshDataAsset() when saving prefab {0}", gameObjectInPrefab.name);

            var surfaces = gameObjectInPrefab.GetComponentsInChildren<NavMeshSurface>(true);
            foreach (var surface in surfaces)
                DeleteStoredPrefabNavMeshDataAsset(surface);
        }

        void DeleteStoredPrefabNavMeshDataAsset(NavMeshSurface surface)
        {
            for (var i = m_PrefabNavMeshDataAssets.Count - 1; i >= 0; i--)
            {
                var storedAssetInfo = m_PrefabNavMeshDataAssets[i];
                if (storedAssetInfo.Surface == surface)
                {
                    var storedNavMeshData = storedAssetInfo.NavMeshData;
                    if (storedNavMeshData != null && storedNavMeshData != surface.navMeshData)
                    {
                        var assetPath = AssetDatabase.GetAssetPath(storedNavMeshData);
                        AssetDatabase.DeleteAsset(assetPath);
                    }

                    m_PrefabNavMeshDataAssets.RemoveAt(i);
                    break;
                }
            }

            if (m_PrefabNavMeshDataAssets.Count == 0)
            {
                PrefabStage.prefabSaving -= DeleteStoredNavMeshDataAssetsForOwnedSurfaces;
                PrefabStage.prefabStageClosing -= ForgetUnsavedNavMeshDataChanges;
            }
        }

        void ForgetUnsavedNavMeshDataChanges(PrefabStage prefabStage)
        {
            // Debug.Log("On prefab closing - forget about this object's surfaces and stop caring about prefab saving");

            if (prefabStage == null)
                return;

            var allSurfacesInPrefab = prefabStage.prefabContentsRoot.GetComponentsInChildren<NavMeshSurface>(true);
            NavMeshSurface surfaceInPrefab = null;
            var index = 0;
            do
            {
                if (allSurfacesInPrefab.Length > 0)
                    surfaceInPrefab = allSurfacesInPrefab[index];

                for (var i = m_PrefabNavMeshDataAssets.Count - 1; i >= 0; i--)
                {
                    var storedPrefabInfo = m_PrefabNavMeshDataAssets[i];
                    if (storedPrefabInfo.Surface == null)
                    {
                        // Debug.LogFormat("A surface from the prefab got deleted after it has baked a new NavMesh but it hasn't saved it. Now the unsaved asset gets deleted. ({0})", storedPrefabI

                        // surface got deleted, thus delete its initial NavMeshData asset
                        if (storedPrefabInfo.NavMeshData != null)
                        {
                            var assetPath = AssetDatabase.GetAssetPath(storedPrefabInfo.NavMeshData);
                            AssetDatabase.DeleteAsset(assetPath);
                        }

                        m_PrefabNavMeshDataAssets.RemoveAt(i);
                    }
                    else if (surfaceInPrefab != null && storedPrefabInfo.Surface == surfaceInPrefab)
                    {
                        //Debug.LogFormat("The surface {0} from the prefab was storing the original navmesh data and now will be forgotten", surfaceInPrefab);

                        var baseSurface = PrefabUtility.GetCorrespondingObjectFromSource(surfaceInPrefab) as NavMeshSurface;
                        if (baseSurface == null || surfaceInPrefab.navMeshData != baseSurface.navMeshData)
                        {
                            var assetPath = AssetDatabase.GetAssetPath(surfaceInPrefab.navMeshData);
                            AssetDatabase.DeleteAsset(assetPath);

                            //Debug.LogFormat("The surface {0} from the prefab has baked new NavMeshData but did not save this change so the asset has been now deleted. ({1})",
                            //    surfaceInPrefab, assetPath);
                        }

                        m_PrefabNavMeshDataAssets.RemoveAt(i);
                    }
                }
            } while (++index < allSurfacesInPrefab.Length);

            if (m_PrefabNavMeshDataAssets.Count == 0)
            {
                PrefabStage.prefabSaving -= DeleteStoredNavMeshDataAssetsForOwnedSurfaces;
                PrefabStage.prefabStageClosing -= ForgetUnsavedNavMeshDataChanges;
            }
        }
    }
}