New exception class if server is malconfigured, e.g. 502

mastodon/Mastodon.py

@@ -2242,6 +2242,8 @@ class Mastodon:
                         # on any 404
                 elif response_object.status_code == 401:
                     ex_type = MastodonUnauthorizedError
+                elif response_object.status_code == 502:
+                    ex_type = MastodonServerError
                 else:
                     ex_type = MastodonAPIError
 
@@ -2528,6 +2530,10 @@ class MastodonAPIError(MastodonError):
     """Raised when the mastodon API generates a response that cannot be handled"""
     pass
 
+class MastodonServerError(MastodonError):
+    """Raised if the Server is malconfigured, e.g. returns a 502 error code"""
+    pass
+
 class MastodonNotFoundError(MastodonAPIError):
     """Raised when the mastodon API returns a 404 Not Found error"""
     pass