title: Invalid syntax using np.zeros
body: <p>I would like to write this:</p>
  
  <pre><code>x = 'something_{}'.format(1)
  exec('{} = {}'.format(x,np.zeros((2,2))))
  </code></pre>
  
  <p>Problem: I get <code>SyntaxError: invalid syntax</code> and I don't know how to solve it.</p>
  
  <p>Someone has an idea?</p>