diff --git a/Lib/_collections_abc.py b/Lib/_collections_abc.py
index 86eb042e3a75ab1..6cef19033b83461 100644
--- a/Lib/_collections_abc.py
+++ b/Lib/_collections_abc.py
@@ -1013,20 +1013,10 @@ def index(self, value, start=0, stop=None):
            Supporting start and stop arguments is optional, but
            recommended.
         '''
-        if start is not None and start < 0:
-            start = max(len(self) + start, 0)
-        if stop is not None and stop < 0:
-            stop += len(self)
-
-        i = start
-        while stop is None or i < stop:
-            try:
-                v = self[i]
-                if v is value or v == value:
-                    return i
-            except IndexError:
-                break
-            i += 1
+        for i in range(len(self))[start:stop]:
+            v = self[i]
+            if v is value or v == value:
+                return i
         raise ValueError
 
     def count(self, value):
@@ -1094,9 +1084,11 @@ def reverse(self):
     def extend(self, values):
         'S.extend(iterable) -- extend sequence by appending elements from the iterable'
         if values is self:
-            values = list(values)
-        for v in values:
-            self.append(v)
+            for i in range(len(values)):
+                self.append(values[i])
+        else:
+            for v in values:
+                self.append(v)
 
     def pop(self, index=-1):
         '''S.pop([index]) -> item -- remove and return item at index (default last).