profile_dir

IPython/core/application.py

@@ -146,7 +146,7 b' class BaseIPythonApplication(Application):'
         return d
     
     _in_init_profile_dir = False
-    profile_dir = Instance(ProfileDir)
+    profile_dir = Instance(ProfileDir, allow_none=True)
     def _profile_dir_default(self):
         # avoid recursion
         if self._in_init_profile_dir:

jupyter_nbformat/sign.py

@@ -87,7 +87,7 b' def signature_removed(nb):'
 class NotebookNotary(LoggingConfigurable):
     """A class for computing and verifying notebook signatures."""
     
-    profile_dir = Instance("IPython.core.profiledir.ProfileDir")
+    profile_dir = Instance("IPython.core.profiledir.ProfileDir", allow_none=True)
     def _profile_dir_default(self):
         from IPython.core.application import BaseIPythonApplication
         app = None