# https://github.com/smontanaro/pylockfile/commit/379fa0b6131995f96f5bd048906fc0bd3c2527f7
# https://github.com/smontanaro/pylockfile/commit/eeead7d35e9a97b457b90edd241fd031df68d57b
# https://github.com/smontanaro/pylockfile/commit/bf2627a5b9f83e1bbcf1b5030a693acb6236a211
--- a/lockfile/__init__.py
+++ b/lockfile/__init__.py
@@ -1,4 +1,3 @@
-
 """
 lockfile.py - Platform-independent advisory file locks.
 
@@ -50,6 +49,8 @@ Exceptions:
             NotMyLock - File was locked but not by the current thread/process
 """
 
+from __future__ import absolute_import
+
 import sys
 import socket
 import os
@@ -257,7 +258,7 @@ def LinkFileLock(*args, **kwds):
     Do not use in new code.  Instead, import LinkLockFile from the
     lockfile.linklockfile module.
     """
-    import linklockfile
+    from . import linklockfile
     return _fl_helper(linklockfile.LinkLockFile, "lockfile.linklockfile",
                       *args, **kwds)
 
@@ -267,7 +268,7 @@ def MkdirFileLock(*args, **kwds):
     Do not use in new code.  Instead, import MkdirLockFile from the
     lockfile.mkdirlockfile module.
     """
-    import mkdirlockfile
+    from . import mkdirlockfile
     return _fl_helper(mkdirlockfile.MkdirLockFile, "lockfile.mkdirlockfile",
                       *args, **kwds)
 
@@ -277,7 +278,7 @@ def SQLiteFileLock(*args, **kwds):
     Do not use in new code.  Instead, import SQLiteLockFile from the
     lockfile.mkdirlockfile module.
     """
-    import sqlitelockfile
+    from . import sqlitelockfile
     return _fl_helper(sqlitelockfile.SQLiteLockFile, "lockfile.sqlitelockfile",
                       *args, **kwds)
 
@@ -306,10 +307,10 @@ def locked(path, timeout=None):
     return decor
 
 if hasattr(os, "link"):
-    import linklockfile as _llf
+    from . import linklockfile as _llf
     LockFile = _llf.LinkLockFile
 else:
-    import mkdirlockfile as _mlf
+    from . import mkdirlockfile as _mlf
     LockFile = _mlf.MkdirLockFile
 
 FileLock = LockFile
diff --git a/lockfile/pidlockfile.py b/lockfile/pidlockfile.py
index 3fc8f63..a965ba8 100644
--- a/lockfile/pidlockfile.py
+++ b/lockfile/pidlockfile.py
@@ -78,7 +78,7 @@ class PIDLockFile(LockBase):
         while True:
             try:
                 write_pid_to_pidfile(self.path)
-            except OSError, exc:
+            except OSError as exc:
                 if exc.errno == errno.EEXIST:
                     # The lock creation failed.  Maybe sleep a bit.
                     if timeout is not None and time.time() > end_time:
@@ -159,7 +159,7 @@ def write_pid_to_pidfile(pidfile_path):
 
         """
     open_flags = (os.O_CREAT | os.O_EXCL | os.O_WRONLY)
-    open_mode = 0644
+    open_mode = 0o644
     pidfile_fd = os.open(pidfile_path, open_flags, open_mode)
     pidfile = os.fdopen(pidfile_fd, 'w')
 
@@ -186,7 +186,7 @@ def remove_existing_pidfile(pidfile_path):
         """
     try:
         os.remove(pidfile_path)
-    except OSError, exc:
+    except OSError as exc:
         if exc.errno == errno.ENOENT:
             pass
         else:
diff --git a/lockfile/sqlitelockfile.py b/lockfile/sqlitelockfile.py
index ec75490..d596229 100644
--- a/lockfile/sqlitelockfile.py
+++ b/lockfile/sqlitelockfile.py
@@ -3,6 +3,11 @@ from __future__ import absolute_import, division
 import time
 import os
 
+try:
+    unicode
+except NameError:
+    unicode = str
+
 from . import LockBase, NotLocked, NotMyLock, LockTimeout, AlreadyLocked
 
 class SQLiteLockFile(LockBase):