diff --git a/hpvm/tools/py-approxhpvm/main.py.in b/hpvm/tools/py-approxhpvm/main.py.in
index 804710b94222dc90930ce7f16149b4135148b2b2..3446b07c1e8e19a9605aef1dea89f53ee2f4e93a 100644
--- a/hpvm/tools/py-approxhpvm/main.py.in
+++ b/hpvm/tools/py-approxhpvm/main.py.in
@@ -157,7 +157,7 @@ def parse_args():
         help="File to approximation configurations; required for 'tensor' target"
     )
     parser.add_argument(
-        "-I", "--include", type=Path, nargs="+",
+        "-I", "--include", type=Path, action="append",
         help="Additional include directories to use"
     )