diff --git a/src/sage/graphs/digraph.py b/src/sage/graphs/digraph.py
index f7749d256e4..6d842df21e6 100644
--- a/src/sage/graphs/digraph.py
+++ b/src/sage/graphs/digraph.py
@@ -1127,7 +1127,7 @@ def to_undirected(self, implementation='c_graph', data_structure=None,
         Immutable graphs yield immutable graphs (:trac:`17005`)::
 
             sage: DiGraph([[1, 2]], immutable=True).to_undirected()._backend
-            <class 'sage.graphs.base.static_sparse_backend.StaticSparseBackend'>
+            <type 'sage.graphs.base.static_sparse_backend.StaticSparseBackend'>
         """
         if sparse is not None:
             if data_structure is not None:
diff --git a/src/sage/graphs/generic_graph.py b/src/sage/graphs/generic_graph.py
index ee71616aead..5931195c1fe 100644
--- a/src/sage/graphs/generic_graph.py
+++ b/src/sage/graphs/generic_graph.py
@@ -950,27 +950,27 @@ def copy(self, weighted=None, implementation='c_graph', data_structure=None,
         Which backend ?::
 
             sage: G.copy(data_structure="sparse")._backend
-            <class 'sage.graphs.base.sparse_graph.SparseGraphBackend'>
+            <type 'sage.graphs.base.sparse_graph.SparseGraphBackend'>
             sage: G.copy(data_structure="dense")._backend
-            <class 'sage.graphs.base.dense_graph.DenseGraphBackend'>
+            <type 'sage.graphs.base.dense_graph.DenseGraphBackend'>
             sage: G.copy(data_structure="static_sparse")._backend
-            <class 'sage.graphs.base.static_sparse_backend.StaticSparseBackend'>
+            <type 'sage.graphs.base.static_sparse_backend.StaticSparseBackend'>
             sage: G.copy(immutable=True)._backend
-            <class 'sage.graphs.base.static_sparse_backend.StaticSparseBackend'>
+            <type 'sage.graphs.base.static_sparse_backend.StaticSparseBackend'>
             sage: G.copy(immutable=True, sparse=True)._backend
-            <class 'sage.graphs.base.static_sparse_backend.StaticSparseBackend'>
+            <type 'sage.graphs.base.static_sparse_backend.StaticSparseBackend'>
             sage: G.copy(immutable=False, sparse=True)._backend
-            <class 'sage.graphs.base.sparse_graph.SparseGraphBackend'>
+            <type 'sage.graphs.base.sparse_graph.SparseGraphBackend'>
             sage: G.copy(immutable=False, sparse=False)._backend
-            <class 'sage.graphs.base.sparse_graph.SparseGraphBackend'>
+            <type 'sage.graphs.base.sparse_graph.SparseGraphBackend'>
             sage: Graph(implementation="networkx").copy(implementation='c_graph')._backend
-            <class 'sage.graphs.base.sparse_graph.SparseGraphBackend'>
+            <type 'sage.graphs.base.sparse_graph.SparseGraphBackend'>
 
         Fake immutable graphs::
 
             sage: G._immutable = True
             sage: G.copy()._backend
-            <class 'sage.graphs.base.sparse_graph.SparseGraphBackend'>
+            <type 'sage.graphs.base.sparse_graph.SparseGraphBackend'>
         """
         # Which data structure should be used ?
         if implementation != 'c_graph':
@@ -14318,7 +14318,7 @@ def union(self, other):
 
             sage: g = g.copy(immutable=True)
             sage: (2*g)._backend
-            <class 'sage.graphs.base.static_sparse_backend.StaticSparseBackend'>
+            <type 'sage.graphs.base.static_sparse_backend.StaticSparseBackend'>
         """
         if (self._directed and not other._directed) or (not self._directed and other._directed):
             raise TypeError('both arguments must be of the same class')
diff --git a/src/sage/graphs/graph.py b/src/sage/graphs/graph.py
index 881dbfbd1fd..ada859d260a 100644
--- a/src/sage/graphs/graph.py
+++ b/src/sage/graphs/graph.py
@@ -4715,7 +4715,7 @@ def to_directed(self, implementation='c_graph', data_structure=None,
         Immutable graphs yield immutable graphs::
 
             sage: Graph([[1, 2]], immutable=True).to_directed()._backend
-            <class 'sage.graphs.base.static_sparse_backend.StaticSparseBackend'>
+            <type 'sage.graphs.base.static_sparse_backend.StaticSparseBackend'>
 
         :trac:`17005`::