Add PackIndex.iter_prefix

tests/test_pack.py

@@ -127,8 +127,12 @@ class PackIndexTests(PackTests):
     def test_iter_prefix(self):
         p = self.get_pack_index(pack1_sha)
         self.assertEqual([p.object_sha1(178)], list(p.iter_prefix(hex_to_sha(a_sha))))
-        self.assertEqual([p.object_sha1(178)], list(p.iter_prefix(hex_to_sha(a_sha)[:5])))
-        self.assertEqual([p.object_sha1(178)], list(p.iter_prefix(hex_to_sha(a_sha)[:2])))
+        self.assertEqual(
+            [p.object_sha1(178)], list(p.iter_prefix(hex_to_sha(a_sha)[:5]))
+        )
+        self.assertEqual(
+            [p.object_sha1(178)], list(p.iter_prefix(hex_to_sha(a_sha)[:2]))
+        )
 
     def test_index_len(self):
         p = self.get_pack_index(pack1_sha)