title: How to pass the StringBuilder parameter in C# to ctypes in python, which is not the normal ctypes supported datatype
body: <p>I am working on the project, which there is c# project use the dll like that:</p>
  
  <pre><code>    public string GetMachineKey()
      {
          StringBuilder buff = new StringBuilder();
          buff.Length = 128;
          ZwCommDll.GetCPUMachineKey(buff, 128);
          string mk = buff.ToString();
          return mk;
      }
  </code></pre>
  
  <p>and I want do it similily in python use the ctypes.</p>
  
  <p>But i am so comfused by the StringBuilder DataType.</p>
  
  <p>Thanks very much your help.</p>