open lazyexpr don't fail if missing operands (wip)

Author: jdavid

src/blosc2/lazyexpr.py

@@ -3083,7 +3083,10 @@ def _open_lazyarray(array):
     for key, value in operands.items():
         if isinstance(value, str):
             value = parent_path / value
-            op = blosc2.open(value)
+            try:
+                op = blosc2.open(value)
+            except FileNotFoundError:
+                op = None
             operands_dict[key] = op
         elif isinstance(value, dict):
             # C2Array