Make a copy of the data upon adding

Should this simple one-liner already solve #22 (closed) ? Please check. If it does not, please provide a minimum working (well, failing) example for me to test, thanks!

src/icartt/dataset.py

@@ -87,18 +87,20 @@ class DataStore1001:
         """
         if not isinstance(newData, np.ndarray):
             raise TypeError("Input data needs to be numpy ndarray.")
-        if newData.dtype.names is None:
+
+        workData = newData.copy()
+        if workData.dtype.names is None:
             try:
-                newData.dtype = [(name, newData.dtype) for name in self.varnames]
+                workData.dtype = [(name, workData.dtype) for name in self.varnames]
             except:
                 ValueError(
                     "Could not assign names to data structure, are you providing an array containing all variables?"
                 )
 
         if self.data is None:
-            self.data = newData
+            self.data = workData
         else:
-            self.data = np.append(self.data, newData)
+            self.data = np.append(self.data, workData)
 
     def denanify(self, d):
         dd = d.copy()