Merge pull request #26 from peppelinux/master

py35 support

Author: rohe

README.md

@@ -1,7 +1,7 @@
 # cryptojwt
 
 ![License](https://img.shields.io/badge/license-Apache%202-blue.svg)
-![Python version](https://img.shields.io/badge/python-3.6%20%7C%203.7-blue.svg)
+![Python version](https://img.shields.io/badge/python-3.5%20%7C%203.6%20%7C%203.7-blue.svg)
 
 An implementation of the JSON cryptographic specs JWS, JWE, JWK, and JWA [RFC 7515-7518] and JSON Web Token (JWT) [RFC 7519]
 

src/cryptojwt/tools/keygen.py

@@ -43,7 +43,7 @@ def main():
                         dest='rsa_exp',
                         type=int,
                         metavar='exponent',
-                        help=f'RSA public key exponent (default {DEFAULT_RSA_EXP})',
+                        help='RSA public key exponent (default {})'.format(DEFAULT_RSA_EXP),
                         default=DEFAULT_RSA_EXP)
     parser.add_argument('--kid',
                         dest='kid',
@@ -66,7 +66,7 @@ def main():
         randomkey = os.urandom(args.keysize)
         jwk = SYMKey(key=randomkey, kid=args.kid)
     else:
-        print(f"Unknown key type: {args.kty}", file=sys.stderr)
+        print("Unknown key type: {}".format(args.kty), file=sys.stderr)
         exit(1)
 
     jwk_dict = jwk.serialize(private=True)