title: 'Series' object has no attribute 'flatten' when I use y.flatten()
body: <p>I am stuck here since last night everything was working just fine and now this.</p>
  
  <p>May I know what the bug is?</p>
  
  <p>Its just frustrating.</p>
  
  <p>I am trying to implement sigmoid function for a give data set.</p>
  
  <p>I want to change its orientation basically for theat I have used y.flatten which is giving me above mentioned error.</p>