[setDim] add checks for labels setter

Author: jgrewe

nixio/data_array.py

@@ -91,13 +91,6 @@ def append_set_dimension(self, labels=None):
         index = len(self.dimensions) + 1
         setdim = SetDimension.create_new(self, index)
         if labels is not None:
-            if not hasattr(labels, '__iter__') or isinstance(labels, str):
-                raise ValueError('`labels` has to be a list-like object.')
-            for label in labels:
-                if not isinstance(label, str):
-                    raise ValueError(f'`labels` has to contain string objects, not {type(label)}')
-            if not isinstance(labels, list):
-                labels = list(labels)
             setdim.labels = labels
         if self.file.auto_update_timestamps:
             self.force_updated_at()

nixio/dimensions.py

@@ -684,6 +684,13 @@ def labels(self, labels):
             raise RuntimeError("The labels of a SetDimension linked to a "
                                "data object cannot be modified")
         dt = util.vlen_str_dtype
+        if not hasattr(labels, '__iter__') or isinstance(labels, str):
+            raise ValueError('`labels` has to be a list-like object.')
+        for label in labels:
+            if not isinstance(label, str):
+                raise ValueError(f'`labels` has to contain string objects, not {type(label)}')
+        if not isinstance(labels, list):
+            labels = list(labels)
         self._h5group.write_data("labels", labels, dtype=dt)
 
     def index_of(self, position, mode=IndexMode.LessOrEqual):