diff --git a/src/calibre/ebooks/rtf2xml/paragraph_def.py b/src/calibre/ebooks/rtf2xml/paragraph_def.py
index 82962fe9ea..0812e15776 100755
--- a/src/calibre/ebooks/rtf2xml/paragraph_def.py
+++ b/src/calibre/ebooks/rtf2xml/paragraph_def.py
@@ -608,12 +608,10 @@ if another paragraph_def is found, the state changes to collect_tokens.
         # when determining uniqueness for a style, ingorne these values, since
         # they don't tell us if the style is unique
         ignore_values = ['style-num', 'nest-level', 'in-table']
-        keys = self.__att_val_dict.keys()
-        keys.sort()
-        for key in keys:
-            if key in ignore_values:
+        for k, v in self.__att_val_dict.items():
+            if k in ignore_values:
                 continue
-            my_string += '%s:%s' % (key, self.__att_val_dict[key])
+            my_string += '%s:%s' % (k, v)
         if my_string in self.__style_num_strings:
             num = self.__style_num_strings.index(my_string)
             num += 1  # since indexing starts at zero, rather than 1
@@ -637,12 +635,9 @@ if another paragraph_def is found, the state changes to collect_tokens.
             the_value = self.__att_val_dict['tabs']
             # the_value = the_value[:-1]
             style_string += ('<%s>%s' % ('tabs', the_value))
-        keys = self.__att_val_dict.keys()
-        keys.sort()
-        for key in keys:
-            if key != 'name' and key !='style-num' and key != 'in-table'\
-              and key not in tabs_list:
-                style_string += ('<%s>%s' % (key, self.__att_val_dict[key]))
+        for k, v in self.__att_val_dict.items():
+            if k not in ['name', 'style-num', 'in-table'] + tabs_list:
+                style_string += ('<%s>%s' % (k, v))
         style_string += '\n'
         self.__body_style_strings.append(style_string)
 
@@ -690,11 +685,9 @@ if another paragraph_def is found, the state changes to collect_tokens.
             the_value = self.__att_val_dict['tabs']
             # the_value = the_value[:-1]
             self.__write_obj.write('<%s>%s' % ('tabs', the_value))
-        keys = self.__att_val_dict.keys()
-        keys.sort()
+        keys = sorted(self.__att_val_dict.keys())
         for key in keys:
-            if key != 'name' and key !='style-num' and key != 'in-table'\
-              and key not in tabs_list:
+            if key not in ['name', 'style-num', 'in-table'] + tabs_list:
                 self.__write_obj.write('<%s>%s' % (key, self.__att_val_dict[key]))
         self.__write_obj.write('\n')
         self.__write_obj.write(self.__start2_marker)