anchor.diff:        sha256 = "0qyqq9akm4vshhn8cngjc1qykcvsn7cz6dlm6njfsgpbraqrmbbw";
       };
   
  -    buildInputs = with self; [
  -      enum34
  +    buildInputs = optionals (pythonOlder "3.4") [
  +      self.enum34
       ];
     };
   
  
positive.code:     propagatedBuildInputs = with self; [
        cffi
        cryptography
        enum34
        idna
        ipaddress
        ndg-httpsclient
  
negative.code: 
      propagatedBuildInputs = with self; [
        cffi
        idna
        ipaddress
        pyasn1
      ] ++ optionals (pythonOlder "3.4") [
        enum34
      ];
  
    };
  