title: Value Error: Too many values to unpack
body: <p>When I execute it, it is giving me an eror i.e too many values to unpack?
  How do i make it to work properly. </p>
  
  <pre><code>  stack = util.Stack()
    closed = []
    child = []
    index = 0
    currNode = problem.getStartState()
    node = currNode
    stack.push(node)
    while not stack.isEmpty():
       node = stack.pop()
       if problem.isGoalState(node):
          print "true"
          closed.append(node)
       else:
           child = problem.getSuccessors(node)
           for nodes in child:
              stack.push(nodes)
           closed.append(node)
    return None      
  </code></pre>
  
  <p>Error is:</p>
  
  <pre><code> File  line 90, in depthFirstSearch
      child = problem.getSuccessors(node)
    File  line 179, in getSuccessors
      x,y = state
  **ValueError: too many values to unpack**
  </code></pre>
  
  <p>The code for the getsuccessor func is:</p>
  
  <pre><code>def getSuccessors(self, state):
      """
      Returns successor states, the actions they require, and a cost of 1.
  
       """
  
      successors = []
      for action in [Directions.NORTH, Directions.SOUTH, Directions.EAST, Directions.WEST]:
        x,y = state
        dx, dy = Actions.directionToVector(action)
        nextx, nexty = int(x + dx), int(y + dy)
        if not self.walls[nextx][nexty]:
          nextState = (nextx, nexty)
          cost = self.costFn(nextState)
          successors.append( ( nextState, action, cost) )
  </code></pre>
  
  <p>The values returned for this function initially:</p>
  
  <pre><code>problem.getStartState() - (5, 5)
  problem.isGoalState(problem.getStartState())- False
   problem.getSuccessors(problem.getStartState()) - [((5, 4), 'South', 1), ((4, 5), 'West', 1)]
  </code></pre>