Fix headers and autentication

topdesk_client/client.py

@@ -71,14 +71,17 @@ class Endpoints:
 class TopDeskClient:
     def __init__(self,
                  url,
-                 username,
-                 password,
+                 username=None,
+                 password=None,
                  headers={},
                  rewrite_url=None):
         self.urls = Endpoints(url)
         self.rewrite_url = rewrite_url
         self.headers = headers
-        self.auth = requests.auth.HTTPBasicAuth(username, password)
+        if username and password:
+            self.auth = requests.auth.HTTPBasicAuth(username, password)
+        else:
+            self.auth = None
 
     def _build_headers(self, headers):
         request_headers = {}
@@ -103,7 +106,7 @@ class TopDeskClient:
                              (url if self.rewrite_url is None
                               else url.replace(*self.rewrite_url)),
                              auth=self.auth,
-                             headers=(None if headers is None else
+                             headers=(self._build_headers({}) if headers is None else
                                       self._build_headers(headers)),
                              params=params if params is not None else {},
                              **kwargs)