title: Return the sum of values returned by another method of all the instances of that class?
body: <pre><code>class Square():
      def __init__(self, side):
          self.side = side
  
      def getArea(self):
          return side*side
  
      def getAreaOfAllInstances(self):
         {need to write this method}
  
  s1 = Square(2)
  s2 = Square(3)
  
  print(s1.getAreaOfAllInstances()) ===&gt; This should print 13 (2*2 + 3*3)
  print(s2.getAreaOfAllInstances()) ===&gt; This should print 13 (2*2 + 3*3)`
  </code></pre>