matplotlib
diff --git a/‎src/napari_matplotlib/histogram.py
Copy file name to clipboardExpand all lines: src/napari_matplotlib/histogram.py
+4-4Lines changed: 4 additions & 4 deletions b/‎src/napari_matplotlib/histogram.py
Copy file name to clipboardExpand all lines: src/napari_matplotlib/histogram.py
+4-4Lines changed: 4 additions & 4 deletions
diff --git a/‎src/napari_matplotlib/tests/test_histogram.py
Copy file name to clipboardExpand all lines: src/napari_matplotlib/tests/test_histogram.py
+3-3Lines changed: 3 additions & 3 deletions b/‎src/napari_matplotlib/tests/test_histogram.py
Copy file name to clipboardExpand all lines: src/napari_matplotlib/tests/test_histogram.py
+3-3Lines changed: 3 additions & 3 deletions
@@ -122,7 +122,7 @@ def _get_valid_axis_keys(self) -> List[str]:
         else:
             return self.layers[0].features.keys()
 
-    def _get_data(self) -> Tuple[npt.NDArray[Any], str]:
+    def _get_data(self) -> Tuple[Optional[npt.NDArray[Any]], str]:
         """Get the plot data.
 
         Returns
@@ -137,12 +137,12 @@ def _get_data(self) -> Tuple[npt.NDArray[Any], str]:
         if not hasattr(self.layers[0], "features"):
             # if the selected layer doesn't have a featuretable,
             # skip draw
-            return [], ""
+            return None, ""
 
         feature_table = self.layers[0].features
 
         if (len(feature_table) == 0) or (self.x_axis_key is None):
-            return [], ""
+            return None, ""
 
         data = feature_table[self.x_axis_key]
         x_axis_name = self.x_axis_key.replace("_", " ")
@@ -164,7 +164,7 @@ def draw(self) -> None:
         """Clear the axes and histogram the currently selected layer/slice."""
         data, x_axis_name = self._get_data()
 
-        if len(data) == 0:
+        if data is None:
             return
 
         self.axes.hist(data, bins=50, edgecolor="white", linewidth=0.3)
 
@@ -1,5 +1,6 @@
 from copy import deepcopy
 
+import numpy as np
 import pytest
 
 from napari_matplotlib import FeaturesHistogramWidget, HistogramWidget
@@ -35,8 +36,6 @@ def test_histogram_3D(make_napari_viewer, brain_data):
 
 
 def test_feature_histogram(make_napari_viewer):
-    import numpy as np
-
     n_points = 1000
     random_points = np.random.random((n_points, 3)) * 10
     feature1 = np.random.random(n_points)
@@ -72,7 +71,8 @@ def test_feature_histogram(make_napari_viewer):
 
 @pytest.mark.mpl_image_compare
 def test_feature_histogram2(make_napari_viewer):
-    import numpy as np    
+    import numpy as np
+
     np.random.seed(0)
     n_points = 1000
     random_points = np.random.random((n_points, 3)) * 10