update type hinting

Author: samwaseda

structuretoolkit/visualize.py

@@ -806,16 +806,16 @@ def plot_isosurface(
     mesh,
     value,
     structure_plot=None,
-    isomin: float = None,
-    isomax: float = None,
-    surface_fill: float = None,
-    opacity: float = None,
-    surface_count: int = None,
-    colorbar_nticks: int = None,
-    caps: dict = dict(x_show=False, y_show=False, z_show=False),
-    colorscale: str = None,
-    height: float = 600,
-    camera: str = "orthographic",
+    isomin: Optional[float] = None,
+    isomax: Optional[float] = None,
+    surface_fill: Optional[float] = None,
+    opacity: Optional[float] = None,
+    surface_count: Optional[int] = None,
+    colorbar_nticks: Optional[int] = None,
+    caps: Optional[dict] = dict(x_show=False, y_show=False, z_show=False),
+    colorscale: Optional[str] = None,
+    height: Optional[float] = 600,
+    camera: Optional[str] = "orthographic",
     **kwargs
 ):
     """