Issue #6268: Fix seek() method of codecs.open(), don't read the BOM twice
after seek(0)
diff --git a/Lib/codecs.py b/Lib/codecs.py
index a67240a..e903f2e 100644
--- a/Lib/codecs.py
+++ b/Lib/codecs.py
@@ -694,6 +694,10 @@
         self.reader.reset()
         self.writer.reset()
 
+    def seek(self, offset, whence=0):
+        self.reader.seek(offset, whence)
+        self.writer.seek(offset, whence)
+
     def __getattr__(self, name,
                     getattr=getattr):