diff --git a/src/Mod/Fem/importCcxFrdResults.py b/src/Mod/Fem/importCcxFrdResults.py
index 6081027573..054bd589ed 100644
--- a/src/Mod/Fem/importCcxFrdResults.py
+++ b/src/Mod/Fem/importCcxFrdResults.py
@@ -38,9 +38,11 @@ import numpy as np
 
 ########## generic FreeCAD import and export methods ##########
 if open.__module__ == '__builtin__':
-    pyopen = open  # because we'll redefine open below
-elif open.__module__ == 'io': # Python3
-    pyopen = open  # because we'll redefine open below
+    # because we'll redefine open below (Python2)
+    pyopen = open
+elif open.__module__ == 'io':
+    # because we'll redefine open below (Python3)
+    pyopen = open
 
 
 def open(filename):
diff --git a/src/Mod/Fem/importInpMesh.py b/src/Mod/Fem/importInpMesh.py
index 296fa8da78..c9ce186076 100644
--- a/src/Mod/Fem/importInpMesh.py
+++ b/src/Mod/Fem/importInpMesh.py
@@ -37,7 +37,11 @@ import string
 
 ########## generic FreeCAD import and export methods ##########
 if open.__module__ == '__builtin__':
-    pyopen = open  # because we'll redefine open below
+    # because we'll redefine open below (Python2)
+    pyopen = open
+elif open.__module__ == 'io':
+    # because we'll redefine open below (Python3)
+    pyopen = open
 
 
 def open(filename):
diff --git a/src/Mod/Fem/importVTKResults.py b/src/Mod/Fem/importVTKResults.py
index 4e0c40eeec..b76da5da54 100644
--- a/src/Mod/Fem/importVTKResults.py
+++ b/src/Mod/Fem/importVTKResults.py
@@ -37,7 +37,11 @@ import Fem
 
 ########## generic FreeCAD import and export methods ##########
 if open.__module__ == '__builtin__':
-    pyopen = open  # because we'll redefine open below
+    # because we'll redefine open below (Python2)
+    pyopen = open
+elif open.__module__ == 'io':
+    # because we'll redefine open below (Python3)
+    pyopen = open
 
 
 def open(filename):
diff --git a/src/Mod/Fem/importZ88Mesh.py b/src/Mod/Fem/importZ88Mesh.py
index 8f34871f42..41033f12a2 100644
--- a/src/Mod/Fem/importZ88Mesh.py
+++ b/src/Mod/Fem/importZ88Mesh.py
@@ -39,7 +39,11 @@ Debug = False
 
 ########## generic FreeCAD import and export methods ##########
 if open.__module__ == '__builtin__':
-    pyopen = open  # because we'll redefine open below
+    # because we'll redefine open below (Python2)
+    pyopen = open
+elif open.__module__ == 'io':
+    # because we'll redefine open below (Python3)
+    pyopen = open
 
 
 def open(filename):
diff --git a/src/Mod/Fem/importZ88O2Results.py b/src/Mod/Fem/importZ88O2Results.py
index ed95fab29c..6f4aff4295 100644
--- a/src/Mod/Fem/importZ88O2Results.py
+++ b/src/Mod/Fem/importZ88O2Results.py
@@ -38,7 +38,11 @@ Debug = False
 
 ########## generic FreeCAD import and export methods ##########
 if open.__module__ == '__builtin__':
-    pyopen = open  # because we'll redefine open below
+    # because we'll redefine open below (Python2)
+    pyopen = open
+elif open.__module__ == 'io':
+    # because we'll redefine open below (Python3)
+    pyopen = open
 
 
 def open(filename):