Simplify logic

holoviews/element/raster.py

@@ -530,18 +530,18 @@ class ImageStack(Image):
     _vdim_reductions = {1: Image}
 
     def __init__(self, data, kdims=None, vdims=None, **params):
+        _kdims = kdims or self.kdims
         if isinstance(data, list) and len(data) > 0:
             x = np.arange(data[0].shape[1])
             y = np.arange(data[0].shape[0])
-            data_tuple = (x, y, *(d for d in data))
+            data_tuple = (x, y, *data)
         elif isinstance(data, dict):
-            _kdims = kdims or self.kdims
             first = next(v for k, v in data.items() if k not in _kdims)
             # TODO: Make it work with dict which hv.Dimension key
             x = data.get(str(_kdims[0]), np.arange(first.shape[1]))
             y = data.get(str(_kdims[1]), np.arange(first.shape[0]))
             iter_data = (v for k, v in data.items() if k not in _kdims)
-            data_tuple = (x, y, *(d for d in iter_data))
+            data_tuple = (x, y, *iter_data)
         elif isinstance(data, np.ndarray) and data.ndim == 3:
             x = np.arange(data.shape[1])
             y = np.arange(data.shape[0])
@@ -557,7 +557,7 @@ def __init__(self, data, kdims=None, vdims=None, **params):
             if isinstance(data_tuple, tuple):
                 vdims = [Dimension(f"level_{i}") for i in range(len(data_tuple[2:]))]
             elif isinstance(data, dict):
-                vdims = [Dimension(key) for key in data.keys() if key not in (kdims or self.kdims)]
+                vdims = [Dimension(key) for key in data.keys() if key not in _kdims]
         super().__init__(data_tuple, kdims=kdims, vdims=vdims, **params)