sort fix

openlp/core/utils/__init__.py

@@ -395,9 +395,10 @@ def get_natural_key(string):
     """
     key = DIGITS_OR_NONDIGITS.findall(string)
     key = [int(part) if part.isdigit() else get_locale_key(part) for part in key]
-    # Python 3 does not support comparision of different types anymore. So make sure, that we do not compare str and int.
-    #if string[0].isdigit():
-    #    return [''] + key
+    # Python 3 does not support comparision of different types anymore. So make sure, that we do not compare str
+    # and int.
+    if string[0].isdigit():
+        return [b''] + key
     return key