diff --git a/graphstorm-processing/graphstorm_processing/graph_loaders/heterogeneous_graphloader.py b/graphstorm-processing/graphstorm_processing/graph_loaders/heterogeneous_graphloader.py
index e1428b7af9..1777ebf085 100644
--- a/graphstorm-processing/graphstorm_processing/graph_loaders/heterogeneous_graphloader.py
+++ b/graphstorm-processing/graphstorm_processing/graph_loaders/heterogeneous_graphloader.py
@@ -14,7 +14,7 @@
 limitations under the License.
 """
 from .loader_base import GraphLoader
-
+import numpy
 
 class HeterogeneousGraphLoader(GraphLoader):
     """DGL Heterogeneous Graph Loader