Added import for ecdsa singature verification error

boards/models/sync_key.py

@@ -1,5 +1,5 b''
 import base64
-from ecdsa import SigningKey, VerifyingKey
+from ecdsa import SigningKey, VerifyingKey, BadSignatureError
 from django.db import models
 
 TYPE_ECDSA = 'ecdsa'
@@ -30,8 +30,7 b' class KeyPairManager(models.Manager):'
             public = VerifyingKey.from_pem(public_key_str)
             signature_byte = base64.b64decode(signature)
             try:
-                return public.verify(signature_byte,
-                        string.encode())
+                return public.verify(signature_byte, string.encode())
             except BadSignatureError:
                 return False
         else: