Index: Lib/_strptime.py
===================================================================
--- Lib/_strptime.py	(revision 70336)
+++ Lib/_strptime.py	(working copy)
@@ -294,8 +294,13 @@
 
 def _strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
     """Return a time struct based on the input string and the format string."""
+    
+    if isinstance(data_string, bytes):
+        raise TypeError("strptime() argument 1 must be str, not bytes")
+    
     global _TimeRE_cache, _regex_cache
-    with _cache_lock:
+    with _cache_lock:        
+        
         if _getlang() != _TimeRE_cache.locale_time.lang:
             _TimeRE_cache = TimeRE()
             _regex_cache.clear()
Index: Lib/test/test_time.py
===================================================================
--- Lib/test/test_time.py	(revision 70336)
+++ Lib/test/test_time.py	(working copy)
@@ -115,6 +115,10 @@
             except ValueError:
                 self.fail("conversion specifier %r failed with '%s' input." %
                           (format, strf_output))
+        
+    def test_srptime_bytesarg(self):
+        self.assertRaises(TypeError, time.strptime, b'2009', "%Y")
+        
 
     def test_asctime(self):
         time.asctime(time.gmtime(self.t))