comment why the changes and for which python version

IPython/core/tests/test_interactiveshell.py

@@ -610,15 +610,16 b' class TestModules(tt.TempFileMixin, unittest.TestCase):'
 class Negator(ast.NodeTransformer):
     """Negates all number literals in an AST."""
 
+    # for python 3.7 and earlier
     def visit_Num(self, node):
         node.n = -node.n
         return node
 
-    if sys.version_info > (3,8):
-        def visit_Constant(self, node):
-            if isinstance(node.value, int):
-                return self.visit_Num(node)
-            return node
+    # for python 3.8+
+    def visit_Constant(self, node):
+        if isinstance(node.value, int):
+            return self.visit_Num(node)
+        return node
 
 class TestAstTransform(unittest.TestCase):
     def setUp(self):
@@ -681,17 +682,21 b' class TestAstTransform(unittest.TestCase):'
 
 class IntegerWrapper(ast.NodeTransformer):
     """Wraps all integers in a call to Integer()"""
+
+    # for Python 3.7 and earlier
+
+    # for Python 3.7 and earlier
     def visit_Num(self, node):
         if isinstance(node.n, int):
             return ast.Call(func=ast.Name(id='Integer', ctx=ast.Load()),
                             args=[node], keywords=[])
         return node
 
-    if sys.version_info > (3,8):
-        def visit_Constant(self, node):
-            if isinstance(node.value, int):
-                return self.visit_Num(node)
-            return node
+    # For Python 3.8+
+    def visit_Constant(self, node):
+        if isinstance(node.value, int):
+            return self.visit_Num(node)
+        return node
 
 
 class TestAstTransform2(unittest.TestCase):
@@ -734,14 +739,16 b' class TestAstTransform2(unittest.TestCase):'
 
 class ErrorTransformer(ast.NodeTransformer):
     """Throws an error when it sees a number."""
+
+    # for Python 3.7 and earlier
     def visit_Num(self, node):
         raise ValueError("test")
 
-    if sys.version_info > (3,8):
-        def visit_Constant(self, node):
-            if isinstance(node.value, int):
-                return self.visit_Num(node)
-            return node
+    # for Python 3.8+
+    def visit_Constant(self, node):
+        if isinstance(node.value, int):
+            return self.visit_Num(node)
+        return node
 
 
 class TestAstTransformError(unittest.TestCase):
@@ -762,7 +769,8 b' class StringRejector(ast.NodeTransformer):'
     Used to verify that NodeTransformers can signal that a piece of code should
     not be executed by throwing an InputRejected.
     """
-
+    
+    #for python 3.7 and earlier
     def visit_Str(self, node):
         raise InputRejected("test")
 

IPython/core/tests/test_ultratb.py

@@ -384,6 +384,10 b' from IPython.testing.decorators import skipif'
 class TokenizeFailureTest(unittest.TestCase):
     """Tests related to https://github.com/ipython/ipython/issues/6864."""
 
+    # that appear to test that we are handling an exception that can be thrown
+    # by the tokenizer due to a bug that seem to have been fixed in 3.8, though
+    # I'm unsure if other sequences can make it raise this error. Let's just
+    # skip in 3.8 for now
     @skipif(sys.version_info > (3,8))
     def testLogging(self):
         message = "An unexpected error occurred while tokenizing input"