convert lists to numpy arrays (in order to handle non-1D lists)

dap/utils/bsreadext.py

@@ -1,3 +1,4 @@
+import numpy as np
 from bsread.sender import Sender, PUB
 
 
@@ -18,10 +19,20 @@ def pack_bsread_data(orig, prefix, skip=None):
             continue
         if isinstance(v, bool):
             v = int(v)
-        elif isinstance(v, list) and not v:
-            v = None
+        elif isinstance(v, list):
+            # bsread fails for empty lists and non-1D lists
+            v = list_to_array(v)
         data[f"{prefix}:{k}"] = v
     return data
 
 
+def list_to_array(x):
+    try:
+        # let numpy figure out the dtype
+        return np.array(x)
+    except ValueError:
+        # the above fails for ragged lists, which need to be object arrays
+        return np.array(x, dtype=object)
+
+