diff --git a/pyerrors/correlators.py b/pyerrors/correlators.py
index 921ae732..ecb8d525 100644
--- a/pyerrors/correlators.py
+++ b/pyerrors/correlators.py
@@ -897,12 +897,14 @@ class Corr:
         else:
             raise Exception("Unknown datatype " + str(datatype))
 
-    def print(self, range=[0, None]):
-        print(self.__repr__(range))
+    def print(self, print_range=None):
+        print(self.__repr__(print_range))
+
+    def __repr__(self, print_range=None):
+        if print_range is None:
+            print_range = [0, None]
 
-    def __repr__(self, range=[0, None]):
         content_string = ""
-
         content_string += "Corr T=" + str(self.T) + " N=" + str(self.N) + "\n"  # +" filled with"+ str(type(self.content[0][0])) there should be a good solution here
 
         if self.tag is not None:
@@ -910,14 +912,14 @@ class Corr:
         if self.N != 1:
             return content_string
 
-        if range[1]:
-            range[1] += 1
+        if print_range[1]:
+            print_range[1] += 1
         content_string += 'x0/a\tCorr(x0/a)\n------------------\n'
-        for i, sub_corr in enumerate(self.content[range[0]:range[1]]):
+        for i, sub_corr in enumerate(self.content[print_range[0]:print_range[1]]):
             if sub_corr is None:
-                content_string += str(i + range[0]) + '\n'
+                content_string += str(i + print_range[0]) + '\n'
             else:
-                content_string += str(i + range[0])
+                content_string += str(i + print_range[0])
                 for element in sub_corr:
                     content_string += '\t' + ' ' * int(element >= 0) + str(element)
                 content_string += '\n'
diff --git a/pyerrors/input/dobs.py b/pyerrors/input/dobs.py
index 498e88d8..92ae3e35 100644
--- a/pyerrors/input/dobs.py
+++ b/pyerrors/input/dobs.py
@@ -652,7 +652,7 @@ def _dobsdict_to_xmlstring_spaces(d, space='  '):
     return o
 
 
-def create_dobs_string(obsl, name, spec='dobs v1.0', origin='', symbol=[], who=None, enstags={}):
+def create_dobs_string(obsl, name, spec='dobs v1.0', origin='', symbol=[], who=None, enstags=None):
     """Generate the string for the export of a list of Obs or structures containing Obs
     to a .xml.gz file according to the Zeuthen dobs format.
 
@@ -678,6 +678,8 @@ def create_dobs_string(obsl, name, spec='dobs v1.0', origin='', symbol=[], who=N
         Provide alternative enstag for ensembles in the form enstags = {ename: enstag}
         Otherwise, the ensemble name is used.
     """
+    if enstags is None:
+        enstags = {}
     od = {}
     r_names = []
     for o in obsl: