Underscores not dashes for simplicity

jupyterlab_spreadsheet_editor/__init__.py

@@ -0,0 +1,16 @@
+try:
+    from ._version import __version__
+except ImportError:
+    # Fallback when using the package in dev mode without installing
+    # in editable mode with pip. It is highly recommended to install
+    # the package from a stable release or in editable mode: https://pip.pypa.io/en/stable/topics/local-project-installs/#editable-installs
+    import warnings
+    warnings.warn("Importing 'jupyterlab_spreadsheet_editor' outside a proper installation.")
+    __version__ = "dev"
+
+
+def _jupyter_labextension_paths():
+    return [{
+        "src": "labextension",
+        "dest": "spreadsheet-editor"
+    }]