Use public API imports in tests and docs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/source/intro.rst

@@ -133,12 +133,11 @@ Using a MultiGraph
 ~~~~~~~~~~~~~~~~~~
 
 For more control, build a
-:class:`~spqrtree._graph.MultiGraph` directly:
+:class:`~spqrtree.MultiGraph` directly:
 
 .. code-block:: python
 
-   from spqrtree._graph import MultiGraph
-   from spqrtree import SPQRTree
+   from spqrtree import MultiGraph, SPQRTree
 
    g = MultiGraph()
    g.add_edge(0, 1)

tests/test_graph.py

@@ -20,7 +20,7 @@
 import unittest
 from collections.abc import Hashable
 
-from spqrtree._graph import Edge, MultiGraph
+from spqrtree import Edge, MultiGraph
 
 
 class TestEdge(unittest.TestCase):

tests/test_palm_tree.py

@@ -24,7 +24,7 @@ DFS from vertex 1.  Edge insertion order is specified in each test.
 import unittest
 from collections.abc import Hashable
 
-from spqrtree._graph import Edge, MultiGraph
+from spqrtree import Edge, MultiGraph
 from spqrtree._palm_tree import PalmTree, build_palm_tree, phi_key
 
 

tests/test_spqrtree.py

@@ -26,8 +26,13 @@ import unittest
 from collections import deque
 from collections.abc import Hashable
 
-from spqrtree._graph import Edge, MultiGraph
-from spqrtree._spqr import NodeType, SPQRNode, build_spqr_tree
+from spqrtree import (
+    Edge,
+    MultiGraph,
+    NodeType,
+    SPQRNode,
+    build_spqr_tree,
+)
 
 
 def _make_k3() -> MultiGraph:

tests/test_triconnected.py

@@ -25,9 +25,10 @@ edge appearance count.
 import unittest
 from collections.abc import Hashable
 
-from spqrtree._graph import Edge, MultiGraph
-from spqrtree._triconnected import (
+from spqrtree import (
     ComponentType,
+    Edge,
+    MultiGraph,
     TriconnectedComponent,
     find_triconnected_components,
 )