diff --git a/deepmd/utils/graph.py b/deepmd/utils/graph.py
index 031454e4b9..e6ff47b21f 100644
--- a/deepmd/utils/graph.py
+++ b/deepmd/utils/graph.py
@@ -153,7 +153,7 @@ def get_embedding_net_nodes_from_graph_def(graph_def: tf.GraphDef, suffix: str =
         The embedding net nodes within the given tf.GraphDef object
     """
     # embedding_net_pattern = f"filter_type_\d+{suffix}/matrix_\d+_\d+|filter_type_\d+{suffix}/bias_\d+_\d+|filter_type_\d+{suffix}/idt_\d+_\d+|filter_type_all{suffix}/matrix_\d+_\d+|filter_type_all{suffix}/matrix_\d+_\d+_\d+|filter_type_all{suffix}/bias_\d+_\d+|filter_type_all{suffix}/bias_\d+_\d+_\d+|filter_type_all{suffix}/idt_\d+_\d+"
-    if suffix is not "":
+    if suffix != "":
         embedding_net_pattern = EMBEDDING_NET_PATTERN\
             .replace('/idt',    suffix + '/idt')\
             .replace('/bias',   suffix + '/bias')\