Is web hook authentic

IsWebHookAuthentic.cs

        public bool IsAuthenticWebhook(NameValueCollection requestHeaders, string requestBody, string shopifySecretKey)
        {
            string hmacHeader = requestHeaders.Get("X-Shopify-Hmac-SHA256");

            if (string.IsNullOrEmpty(hmacHeader))
            {
                return false;
            }

            HMACSHA256 hmac = new HMACSHA256(Encoding.UTF8.GetBytes(shopifySecretKey));
            string hash = Convert.ToBase64String(hmac.ComputeHash(Encoding.UTF8.GetBytes(requestBody)));

            return hash == hmacHeader; 
}