Lot of cleanup

utils/errors.py

@@ -1,6 +1,25 @@
 
 class Error(Exception):
-    pass
+    status_code = 400
+
+    def __init__(self, message, status_code=None, payload=None):
+        Exception.__init__(self)
+        self.message = message
+        if status_code is not None:
+            self.status_code = status_code
+        self.payload = payload
+
+    def to_dict(self):
+        rv = dict(self.payload or ())
+        rv['message'] = self.message
+        return rv
+
+    def __repr__(self):
+        return f'{self.__class__.__qualname__}({self.message!r}, payload={self.payload!r}, status_code={self.status_code})'
+
+
+class ActivityNotFoundError(Error):
+    status_code = 404
 
 
 class BadActivityError(Error):