Fix vtTransformation type testing with `isinstance`

src/vt/compose_trsf.py

@@ -73,7 +73,7 @@ def compose_trsf(trsfs, params="", **kwargs):
     elif isinstance(trsfs, list):
         if _verbose_ >= 2:
             print("call of '" + str(proc) + "': python library")
-        if type(trsfs[0]) is not vtTransformation:
+        if not isinstance(trsfs[0], vtTransformation):
             if _verbose_ >= 1:
                 print(str(proc) + ": unexpected type '" + str(type(trsfs[0])) + "'for 'trsfs[0]'")
             return None