title: Lambda function doesn't take arguments in the order of their positions
body: <p>I want to integrate <code>a * b**2</code> with the limits <code>a = [0, 2]</code> and <code>b = [0, 1]</code>.</p>
  
  <pre><code>from scipy import integrate
  
  f1 = lambda a, b: a * b ** 2      
  print((integrate.dblquad(f1, 0, 2, 0, 1))[0])
  </code></pre>
  
  <p><code>Output: 1.333...</code></p>
  
  <p>Expected result: 0.666... </p>
  
  <p>What's wrong?: The integration is being done with the limits a = [0, 1] and b = [0, 2]. </p>
  
  <p>Question: Why is lambda not reading the arguments in the order of their position? </p>