diff --git a/tools/import-mbox.py b/tools/import-mbox.py
index 5ce4e81..28c0363 100755
--- a/tools/import-mbox.py
+++ b/tools/import-mbox.py
@@ -571,8 +571,8 @@
     results = imap4.uid('fetch', uids, '(BODY[HEADER.FIELDS (MESSAGE-ID)])')
 
     mail = {}
-    uid_re = re.compile(b'^\d+ \(UID (\d+) BODY\[')
-    mid_re = re.compile(b'^Message-ID:\s*(.*?)\s*$', re.I)
+    uid_re = re.compile(r'^\d+ \(UID (\d+) BODY\[')
+    mid_re = re.compile(r'^Message-ID:\s*(.*?)\s*$', re.I)
     uid = None
     for result in results[1]:
         for line in result: