use assert[Not]IsInstance where appropriate
diff --git a/Lib/test/test_pyclbr.py b/Lib/test/test_pyclbr.py
index ec818d1..8d22fc2 100644
--- a/Lib/test/test_pyclbr.py
+++ b/Lib/test/test_pyclbr.py
@@ -92,12 +92,12 @@
             self.assertHasattr(module, name, ignore)
             py_item = getattr(module, name)
             if isinstance(value, pyclbr.Function):
-                self.assertTrue(isinstance(py_item, (FunctionType, BuiltinFunctionType)))
+                self.assertIsInstance(py_item, (FunctionType, BuiltinFunctionType))
                 if py_item.__module__ != moduleName:
                     continue   # skip functions that came from somewhere else
                 self.assertEquals(py_item.__module__, value.module)
             else:
-                self.assertTrue(isinstance(py_item, (ClassType, type)))
+                self.assertIsInstance(py_item, (ClassType, type))
                 if py_item.__module__ != moduleName:
                     continue   # skip classes that came from somewhere else