def signature
      k_date = hmac('HYPER' + @client.secret_key, @date[0, 8])
      k_region = hmac(k_date, 'us-west-1')
      k_service = hmac(k_region, SERVICE)
      k_credentials = hmac(k_service, KEYPARTS_REQUEST)
      hexhmac(k_credentials, string_to_sign)
    end
def signature
      k_date = hmac('HYPER' + @client.secret_key, @date[0, 8])
      k_region = hmac(k_date, 'us-west-1')
      k_service = hmac(k_region, SERVICE)
      k_credentials = hmac(k_service, KEYPARTS_REQUEST)
      hexhmac(k_credentials, string_to_sign)
    end
setup signature key
 https://docs.hyper.sh/Reference/API/2016-04-04%20[Ver.%201.23]/index.html