diff --git a/python/cuxfilter/charts/bokeh/plots/bar.py b/python/cuxfilter/charts/bokeh/plots/bar.py
index 86d1b9f5..b204e18e 100644
--- a/python/cuxfilter/charts/bokeh/plots/bar.py
+++ b/python/cuxfilter/charts/bokeh/plots/bar.py
@@ -10,7 +10,9 @@ class InteractiveBar(param.Parameterized):
     x = param.String("x", doc="x axis column name")
     y = param.List(["y"], doc="y axis column names as a list")
     source_df = param.ClassSelector(
-        class_=(cudf.DataFrame, pd.DataFrame), default=cudf.DataFrame(), doc="source dataframe"
+        class_=(cudf.DataFrame, pd.DataFrame),
+        default=cudf.DataFrame(),
+        doc="source dataframe",
     )
     box_stream = param.ClassSelector(
         class_=hv.streams.SelectionXY, default=hv.streams.SelectionXY()
diff --git a/python/cuxfilter/charts/core/core_chart.py b/python/cuxfilter/charts/core/core_chart.py
index 4b0d61ee..fa4555de 100644
--- a/python/cuxfilter/charts/core/core_chart.py
+++ b/python/cuxfilter/charts/core/core_chart.py
@@ -62,7 +62,9 @@ def library_specific_params(self):
     def x_dtype(self):
         if isinstance(self.source, ColumnDataSource):
             return self.source.data[self.data_x_axis].dtype
-        elif isinstance(self.source, (cudf.DataFrame, dask_cudf.DataFrame, pd.DataFrame)):
+        elif isinstance(
+            self.source, (cudf.DataFrame, dask_cudf.DataFrame, pd.DataFrame)
+        ):
             return self.source[self.x].dtype
         return None
 
@@ -70,7 +72,9 @@ def x_dtype(self):
     def y_dtype(self):
         if isinstance(self.source, ColumnDataSource):
             return self.source.data[self.data_x_axis].dtype
-        elif isinstance(self.source, (cudf.DataFrame, dask_cudf.DataFrame, pd.DataFrame)):
+        elif isinstance(
+            self.source, (cudf.DataFrame, dask_cudf.DataFrame, pd.DataFrame)
+        ):
             return self.source[self.y].dtype
         return None
 
diff --git a/python/cuxfilter/charts/core/non_aggregate/core_graph.py b/python/cuxfilter/charts/core/non_aggregate/core_graph.py
index 08361319..f0216ec9 100644
--- a/python/cuxfilter/charts/core/non_aggregate/core_graph.py
+++ b/python/cuxfilter/charts/core/non_aggregate/core_graph.py
@@ -170,13 +170,17 @@ def __init__(
 
     @property
     def x_dtype(self):
-        if isinstance(self.nodes, (cudf.DataFrame, dask_cudf.DataFrame, pd.DataFrame)):
+        if isinstance(
+            self.nodes, (cudf.DataFrame, dask_cudf.DataFrame, pd.DataFrame)
+        ):
             return self.nodes[self.node_x].dtype
         return None
 
     @property
     def y_dtype(self):
-        if isinstance(self.nodes, (cudf.DataFrame, dask_cudf.DataFrame, pd.DataFrame)):
+        if isinstance(
+            self.nodes, (cudf.DataFrame, dask_cudf.DataFrame, pd.DataFrame)
+        ):
             return self.nodes[self.node_y].dtype
         return None
 
diff --git a/python/cuxfilter/charts/core/non_aggregate/core_stacked_line.py b/python/cuxfilter/charts/core/non_aggregate/core_stacked_line.py
index 55b793eb..b4982781 100644
--- a/python/cuxfilter/charts/core/non_aggregate/core_stacked_line.py
+++ b/python/cuxfilter/charts/core/non_aggregate/core_stacked_line.py
@@ -31,7 +31,9 @@ def y_dtype(self):
         overwriting the y_dtype property from BaseChart for stackedLines where
         self.y is a list of columns
         """
-        if isinstance(self.source, (cudf.DataFrame, dask_cudf.DataFrame, pd.DataFrame)):
+        if isinstance(
+            self.source, (cudf.DataFrame, dask_cudf.DataFrame, pd.DataFrame)
+        ):
             return self.source[self.y[0]].dtype
         return None
 
diff --git a/python/cuxfilter/charts/panel_widgets/plots.py b/python/cuxfilter/charts/panel_widgets/plots.py
index ad130eeb..8bca3c65 100644
--- a/python/cuxfilter/charts/panel_widgets/plots.py
+++ b/python/cuxfilter/charts/panel_widgets/plots.py
@@ -89,7 +89,9 @@ class DateRangeSlider(BaseWidget):
     def x_dtype(self):
         if isinstance(self.source, ColumnDataSource):
             return self.source.data[self.data_x_axis].dtype
-        elif isinstance(self.source, (cudf.DataFrame, dask_cudf.DataFrame, pd.DataFrame)):
+        elif isinstance(
+            self.source, (cudf.DataFrame, dask_cudf.DataFrame, pd.DataFrame)
+        ):
             return self.source[self.x].dtype
         return None