Make get_operator() work if no operator id

topdesk_client/client.py

@@ -101,25 +101,33 @@ class TopDeskClient:
         params['$fields'] = ','.join(fields)
 
     def get_operator(self, identity):
-        if isinstance(identity, Operator):
-            url = self.urls.get_operator(identity.id)
+        def _get_operator_by_id(ident):
+            url = self.urls.get_operator(ident)
             r = self.get(url, return_response=True)
             if r.status_code == 200:
                 return Operator.from_dict(r.json())
             else:
                 return None
-        else:
+
+        def _get_operator_by_username(name):
             url = self.urls.get_operators()
             operators = [Operator.from_dict(x) for x in
                          self.get(url,
-                                  params={'topdesk_login_name': identity})]
-            f = filter(lambda x: x.user_name.lower() == identity,
+                                  params={'topdesk_login_name': name})]
+            f = filter(lambda x: x.user_name.lower() == name,
                        operators)
             try:
                 return next(f)
             except StopIteration:
                 return None
 
+        if isinstance(identity, Operator) and identity.id:
+            return _get_operator_by_id(identity.id)
+        elif isinstance(identity, Operator):
+            return _get_operator_by_username(identity.user_name)
+        else:
+            return _get_operator_by_username(identity)
+
     def create_operator(self, operator):
         url = self.urls.get_operators()
         # TODO: Remove password setting when proper auth arrives