Fix develop command by delaying imports

retrolab/__init__.py

@@ -1,5 +1,4 @@
 from ._version import __version__
-from .app import RetroApp
 from .serverextension import load_jupyter_server_extension
 
 
@@ -12,6 +11,7 @@ def _jupyter_server_extension_paths():
 
 
 def _jupyter_server_extension_points():
+    from .app import RetroApp
     return [{"module": "retrolab", "app": RetroApp}]
 
 

retrolab/serverextension.py

@@ -1,7 +1,5 @@
-from .app import RetroApp
-
-
 def load_jupyter_server_extension(serverapp):
+    from .app import RetroApp
     extension = RetroApp()
     extension.serverapp = serverapp
     extension.load_config_file()