title: Making a 2d list of objects (Python 2.7)
body: <p>I have no experience with object oriented programming. I've program mostly in C so this tends to be a little confusing. Basically I just want to make sure I am doing it correctly. Also, is this a working example of inheritance?</p>
  
  <p>Okay, so I have initialized a 20x20 grid world and set each element to None. </p>
  
  <pre><code>class World:
      def __init__(self):
          self.arr = [[None for x in range(20)] for y in range(20)]
  </code></pre>
  
  <p>Now I need to place an object into a specified element given the x,y coordinates. This is a method of the World class. </p>
  
  <pre><code>def add_attack_robot(self, team, x, y, direction):
          self.arr[x][y] = AttackRobot() &lt;---- **Is this correct?**
  </code></pre>
  
  <p>Here is the AttackRobot class:</p>
  
  <pre><code>class AttackRobot(Robot):
      def __init__(self,team,x,y,direction):
          Robot.__init__(self,team,x,y,direction)
  </code></pre>