diff --git a/smartmeter/dlms.py b/smartmeter/dlms.py
index d8abe3b8e..7a547a06a 100755
--- a/smartmeter/dlms.py
+++ b/smartmeter/dlms.py
@@ -49,7 +49,12 @@
 from threading import Lock
 from typing import (Union, Tuple, Any)
 
-from lib.model.smartplugin import SmartPlugin
+# only for syntax/type checking
+try:
+    from lib.model.smartplugin import SmartPlugin
+except ImportError:
+    pass
+
 
 """
 This module implements the query of a smartmeter using the DLMS protocol.
diff --git a/smartmeter/sml.py b/smartmeter/sml.py
index 760842c6e..c2c35a143 100755
--- a/smartmeter/sml.py
+++ b/smartmeter/sml.py
@@ -51,7 +51,11 @@
 from threading import Lock
 from typing import Union
 
-from lib.model.smartplugin import SmartPlugin
+# only for syntax/type checking
+try:
+    from lib.model.smartplugin import SmartPlugin
+except ImportError:
+    pass
 
 """
 This module implements the query of a smartmeter using the SML protocol.