diff --git a/PyMca5/PyMcaIO/MEDFile.py b/PyMca5/PyMcaIO/MEDFile.py
index 1ea0e961b..84eeaa320 100644
--- a/PyMca5/PyMcaIO/MEDFile.py
+++ b/PyMca5/PyMcaIO/MEDFile.py
@@ -199,7 +199,7 @@ def mca_read_file(self, fname):
                     x, sroi, item = tag.split('_')
                     iroi = int(sroi)
                     if item == "label":
-                        labels = str2str(val, delim='\&')
+                        labels = str2str(val, delim=r'&')
                         if labels[-1] == '':
                             labels = labels[:-1]
                         _roi_n[iroi] = labels
diff --git a/PyMca5/PyMcaIO/NexusUtils.py b/PyMca5/PyMcaIO/NexusUtils.py
index 41f91b60b..64cf31653 100644
--- a/PyMca5/PyMcaIO/NexusUtils.py
+++ b/PyMca5/PyMcaIO/NexusUtils.py
@@ -2,7 +2,7 @@
 #
 # The PyMca X-Ray Fluorescence Toolkit
 #
-# Copyright (c) 2019 European Synchrotron Radiation Facility
+# Copyright (c) 2019-2024 European Synchrotron Radiation Facility
 #
 # This file is part of the PyMca X-ray Fluorescence Toolkit developed at
 # the ESRF by the Software group.
@@ -199,7 +199,7 @@ def isNxClass(h5group, *classes):
     Nexus class of existing h5py.Group (None when no Nexus instance)
 
     :param h5py.Group h5group:
-    :param \*classes: list(str) of Nexus classes
+    :param *classes: list(str) of Nexus classes
     :returns bool:
     """
     return nxClass(h5group) in classes
@@ -208,7 +208,7 @@ def isNxClass(h5group, *classes):
 def raiseIsNxClass(h5group, *classes):
     """
     :param h5py.Group h5group:
-    :param \*classes: list(str) of Nexus classes
+    :param *classes: list(str) of Nexus classes
     :raises RuntimeError:
     """
     if isNxClass(h5group, *classes):
@@ -218,7 +218,7 @@ def raiseIsNxClass(h5group, *classes):
 def raiseIsNotNxClass(h5group, *classes):
     """
     :param h5py.Group h5group:
-    :param \*classes: list(str) of Nexus classes
+    :param *classes: list(str) of Nexus classes
     :raises RuntimeError:
     """
     if not isNxClass(h5group, *classes):