title: How to fix "unsupported operand type(s) for +: 'dict' and 'int'"
body: <p>When I was running the following code in a function, I encountered the following error. However, when I run these lines, there is no error. 
  The error appears at Line 185, TypeError: unsupported operand type(s) for +: 'dict' and 'int'</p>
  
  <p>Line 183 was my original code, which includes a dictionary. But now I'm not using dictionary anymore, whey the error is about dict??</p>
  
  <pre><code>183 #    N_layer = inputs["N_layer"]
  184     N_layer = 18
  185     n_uw = np.zeros((N_layer + 2), dtype=int)
  186     n_dw = np.zeros((N_layer + 2), dtype=int)
  187     n_gas = np.zeros((N_layer + 2), dtype=int)
  </code></pre>
  
  <p>The result should be array of zeros.</p>