unity http request

using UnityEngine;
using UnityEngine.Networking;
using System.Collections;

[[Serializable]
public class TokenClassName
{
    public string access_token;
}

private static IEnumerator GetAccessToken(Action<string> result)
{
    Dictionary<string, string> content = new Dictionary<string, string>();
    //Fill key and value
    content.Add("grant_type", "client_credentials");
    content.Add("client_id", "login-secret");
    content.Add("client_secret", "secretpassword");

    UnityWebRequest www = UnityWebRequest.Post("https://api.home-connect.com/api/homeappliances/{haId}/programs/active -H 'Authorization: Bearer {access_token}'", content);
    //Send request
    yield return www.Send();

    if (!www.isError)
    {
        string resultContent = www.downloadHandler.text;
        TokenClassName json = JsonUtility.FromJson<TokenClassName>(resultContent);

        //Return result
        result(json.access_token);
    }
    else
    {
        //Return null
        result("");
    }
}

public class BenimDatam : BenimDatam
{
    void Start()
    {
        StartCoroutine(Upload());
    }

    IEnumerator Upload()
    {
        WWWForm secenekler_degerleri = new WWWForm();
        WWWForm secenekler = new WWWForm();
        WWWForm veri = new WWWForm();
        WWWForm form = new WWWForm();
        secenekler_degerleri .AddField("ConsumerProducts.CoffeeMaker.Option.BeanAmount", "ConsumerProducts.CoffeeMaker.EnumType.BeanAmount.Strong");
        secenekler_degerleri .AddField("ConsumerProducts.CoffeeMaker.Option.FillQuantity", 35);
        secenekler.AddField("options", secenekler_degerleri);
        veri.AddField("ConsumerProducts.CoffeeMaker.Program.Beverage.Espresso", secenekler);
        form.AddField("data", veri);
        
        

        using (UnityWebRequest www = UnityWebRequest.Post("https://api.home-connect.com/api/homeappliances/{haId}/programs/active -H 'Content-Type: application/vnd.bsh.sdk.v1+json'", form))
        {
            yield return www.SendWebRequest();
            string token = null;

            yield return GetAccessToken((tokenResult) => { token = tokenResult; });

            www.SetRequestHeader("Authorization", "Bearer " + token);
            www.Send();

            if (www.result != UnityWebRequest.Result.Success)
            {
                Debug.Log(www.error);
            }
            else
            {
                Debug.Log("Form upload complete!");
            }
        }
    }
}