Create method to encode and decode idna

Previously strings with characters like "ß" would throw and exception
This seems to happen because the lib behind encode().decode('idna')
cant handle characters like this

powerdnsadmin/lib/utils.py

@@ -4,6 +4,7 @@ import json
 import requests
 import hashlib
 import ipaddress
+import idna
 
 from collections.abc import Iterable
 from distutils.version import StrictVersion
@@ -248,10 +249,27 @@ def pretty_domain_name(value):
         if value.startswith('xn--') \
         or value.find('.xn--') != -1:
             try:
-                return value.encode().decode('idna')
+                return to_idna(value, 'decode')
             except:
-                raise Exception("Cannot decode IDN domain")
+                raise Exception('Cannot decode IDN domain')
         else:
             return value
     else:
-        raise Exception("Require the Punycode in string format")
+        raise Exception('Require the Punycode in string format')
+
+def to_idna(value, action):
+    splits = value.split()
+    result = []
+    if action == 'encode':
+        for split in splits:
+            try:
+                # Try encoding to idna
+                result.append(idna.encode(split).decode())
+            except idna.IDNAError:
+                result.append(split)
+    elif action == 'decode':
+        for split in splits:
+            result.append(idna.decode(split))   
+    else:
+        raise Exception('No valid action received')
+    return ' '.join(result)