title: Function with multiple return values as input in scipy.minimize
body: <p>i am new into python and my task is to minimize math functions which have 3 return values (as provided in a template I must use), but I only need the first one of these returns. Here is an example</p>
  <pre><code>```
  def exponential_function(x):
  
     value = -np.exp(-0.5 * (x[0]**2 + x[1]**2))
     grad = np.array([-value * x[0], -value * x[1]])
  
     return value, grad, np.array([0,0])
  
  ```
  </code></pre>
  <p>this has to be the first argument of optimize.minimize. This would work for only one return (=value), but in this case I have no idea. I tried wrapper functions, which I failed.</p>
  <p>Thank you in advance</p>