diff --git a/cyruslib.py b/cyruslib.py
--- a/cyruslib.py
+++ b/cyruslib.py
@@ -89,6 +89,26 @@
     elif not isinstance(s, (six.text_type, six.binary_type)):
         raise TypeError("not expecting type '%s'" % type(s))
     return s
+def ensure_binary(s, encoding='utf-8', errors='strict'):
+    """Coerce **s** to six.binary_type.
+    For Python 2:
+      - `unicode` -> encoded to `str`
+      - `str` -> `str`
+    For Python 3:
+      - `str` -> encoded to `bytes`
+      - `bytes` -> `bytes`
+
+      Copied from six (not available < 1.12), and extended with list support.
+    """
+    if isinstance(s, list):
+
+        #FIXME pass encoding
+        return list(map(ensure_binary, s))
+    if isinstance(s, six.binary_type):
+        return s
+    if isinstance(s, six.text_type):
+        return s.encode(encoding, errors)
+    raise TypeError("not expecting type '%s'" % type(s))
 
 def ok(res):
     return res.upper().startswith('OK')
@@ -231,7 +251,7 @@
         return ok(res), dat[0]
 
     def getannotation(self, mailbox, pattern='*', shared=None):
-        if shared == None:
+        if shared is None:
             typ, dat = self._simple_command('GETANNOTATION', mailbox, quote(pattern), quote('*'))
         elif shared:
             typ, dat = self._simple_command('GETANNOTATION', mailbox, quote(pattern), quote('value.shared'))
@@ -335,7 +355,7 @@
         return ok(res), dat[0]
 
     def getannotation(self, mailbox, pattern='*', shared=None):
-        if shared == None:
+        if shared is None:
             typ, dat = self._simple_command('GETANNOTATION', mailbox, quote(pattern), quote('*'))
         elif shared:
             typ, dat = self._simple_command('GETANNOTATION', mailbox, quote(pattern), quote('value.shared'))
@@ -651,7 +671,7 @@
         elif self.ENCODING in self.ENCODING_LIST:
             return self.__decode(text)
 
-    def lm(self, pattern="*"):
+    def lm(self, pattern=b"*"):
         """
         List mailboxes, returns dict with list of mailboxes
 
@@ -665,8 +685,8 @@
 
         """
         self.__prepare('LIST')
-        if pattern == '': pattern = "*"
-        if pattern == '%':
+        if pattern == b'': pattern = b"*"
+        if pattern == b'%':
             res, ml = self.__docommand('list', '', '%')
         else:
             res, ml = self.__docommand('list', '""', self.decode(pattern))
@@ -706,7 +726,8 @@
     def dm(self, mailbox, recursive=True):
         """Delete mailbox"""
         self.__prepare('DELETE', mailbox)
-        mbxTmp = mailbox.split(self.SEP)
+        SEPARATOR = ensure_binary(self.SEP)
+        mbxTmp = mailbox.split(SEPARATOR)
         # Cyrus is not recursive for user subfolders and global folders
         if (recursive and mbxTmp[0] != "user") or (len(mbxTmp) > 2):
             mbxList = self.lm("%s%s*" % (mailbox, self.SEP))
@@ -816,7 +837,6 @@
         # calling programs should be fixed instead. 
 
         res, data = self.__docommand("getmetadata", self.decode(mailbox), pattern, shared)
-
         if (len(data) == 1) and data[0] is None:
             self.__verbose( '[GETMETADATA %s] No results' % (mailbox) )
             return {}
@@ -901,7 +921,7 @@
         self.__prepare('LSUB')
         if pattern == '': pattern = "*"
         res, ml = self.__docommand('lsub', '*', pattern)
-
+        ml = ensure_str(ml)
         if not ok(res):
             self.__verbose( '[LIST] %s: %s' % (res, ml) )
             return []