title: why cv2.bitwise_and function of opencv-python returns four element array on single scalar value
body: <p>I'm trying to understand <code>cv2.bitwise_and</code> function of opencv-python. So I tried it as:</p>
  
  <pre><code>import cv2
  cv2.bitwise_and(1,1)
  </code></pre>
  
  <p>above code returns</p>
  
  <pre><code>array([[1.],
         [0.],
         [0.],
         [0.]])
  </code></pre>
  
  <p>I don't understand why it returns this. </p>
  
  <p><a href="https://docs.opencv.org/2.4/modules/core/doc/operations_on_arrays.html#bitwise-and" rel="nofollow noreferrer">Documentation</a> says :</p>
  
  <p><code>dst(I) = src1(I) ^ src2(I) if mask(I) != 0</code> </p>
  
  <p>according to this output should be single value 1. where am I going wrong?</p>