title: Angular http post request appending parenthesis unexpectedly
body: <p>When a request is made. i have seen that extra parenthesis are attached before the request type. like below.</p>
  
  <pre><code>{"username":"demo","password":"123"}POST /authentication/
  </code></pre>
  
  <p>and my back-end is refusing this with error code 405 method not allowed.</p>
  
  <p>Back-end is in <strong>Django rest_framework</strong> and front end is in <strong>Angular 6</strong>.</p>
  
  <p>I don't know how to rid from these parenthesis. Either i have to look into front end, why it is appending these extra parenthesis or i have to see which middle-ware is stopping this in Django. </p>
  
  <p>Sample request code of angular is below:</p>
  
  <pre><code>this.http.post(url, JSON.stringify(datum),{'headers':headers}).subscribe()
  </code></pre>
  
  <p><strong>Edit:</strong>
  Error is coming after each logout request. Whenever I am trying to destroy session during logout either it is successful or not from back-end, error start coming right after that.</p>