diff --git a/Lib/decimal.py b/Lib/decimal.py
index ffe6e9e..cdb88bc 100644
--- a/Lib/decimal.py
+++ b/Lib/decimal.py
@@ -588,7 +588,7 @@
 
         # From a string
         # REs insist on real strings, so we can too.
-        if isinstance(value, basestring):
+        if isinstance(value, str):
             if _isinfinity(value):
                 self._exp = 'F'
                 self._int = (0,)