move tz utils to top-level private module ._tz

notebook/services/contents/filecheckpoints.py

@@ -12,11 +12,12 @@ from .checkpoints import (
 )
 from .fileio import FileManagerMixin
 
-from . import tz
 from ipython_genutils.path import ensure_dir_exists
 from ipython_genutils.py3compat import getcwd
 from traitlets import Unicode
 
+from notebook import _tz as tz
+
 
 class FileCheckpoints(FileManagerMixin, Checkpoints):
     """

notebook/services/contents/filemanager.py

@@ -22,7 +22,8 @@ from .manager import ContentsManager
 from ipython_genutils.importstring import import_item
 from traitlets import Any, Unicode, Bool, TraitError, observe, default, validate
 from ipython_genutils.py3compat import getcwd, string_types
-from . import tz
+
+from notebook import _tz as tz
 from notebook.utils import (
     is_hidden, is_file_hidden,
     to_api_path,

notebook/services/kernels/kernelmanager.py

@@ -17,7 +17,7 @@ from jupyter_client.multikernelmanager import MultiKernelManager
 from traitlets import Dict, List, Unicode, TraitError, default, validate
 
 from notebook.utils import to_os_path
-from notebook.services.contents.tz import utcnow, isoformat
+from notebook._tz import utcnow, isoformat
 from ipython_genutils.py3compat import getcwd
 
 

notebook/services/sessions/tests/test_sessionmanager.py

@@ -9,7 +9,7 @@ from tornado.ioloop import IOLoop
 from ..sessionmanager import SessionManager
 from notebook.services.kernels.kernelmanager import MappingKernelManager
 from notebook.services.contents.manager import ContentsManager
-from notebook.services.contents.tz import utcnow, isoformat
+from notebook._tz import utcnow, isoformat
 
 class DummyKernel(object):
     def __init__(self, kernel_name='python'):