diff --git a/Lib/io.py b/Lib/io.py
index 61206c4..1cf9a18 100644
--- a/Lib/io.py
+++ b/Lib/io.py
@@ -66,6 +66,11 @@
 # open() uses st_blksize whenever we can
 DEFAULT_BUFFER_SIZE = 8 * 1024  # bytes
 
+# for seek()
+SEEK_SET = 0
+SEEK_CUR = 1
+SEEK_END = 2
+
 # py3k has only new style classes
 __metaclass__ = type