title: class instance not iterable
body: <p>In my func, I have:</p>
  
  <pre><code>        """
          Iterates 300 times as attempts, each having an inner-loop
          to calculate the z of a neighboring point and returns the optimal                 
          """
  
          pointList = []
          max_p = None
  
          for attempts in range(300):
  
              neighborList = ( (x - d, y), (x + d, y), (x, y - d), (x, y + d) )
  
              for neighbor in neighborList:
                  z = evaluate( neighbor[0], neighbor[1] )
                  point = None
                  point = Point3D( neighbor[0], neighbor[1], z)
                  pointList += point
              max_p = maxPoint( pointList )
              x = max_p.x_val
              y = max_p.y_val
          return max_p
  </code></pre>
  
  <p>I'm not iterating over my class instance, point, but I nevertheless get:</p>
  
  <pre><code>    pointList += newPoint
  TypeError: 'Point3D' object is not iterable
  </code></pre>