title: 'Node' object is not callable
body: <p>I have the following code:</p>
  
  <pre><code>class Node:
      def __init__(self,data):
          self.data = data
          self.next = None
  class linkedList:
      def __init__(self):
          self.top = None
      def isempty(self):
          return self.top== None
      def push(self,data):
          new_node = Node(data)
          #if self.top ==None:
          #    self.top= new_node
           #   return
          new_node.next = self.top
          self.top = new_node
      def pop(self):
          if self.top ==None:
              print('underflow comdition')
              return
          temp = self.top
          self.top = self.top.next
          return temp.data
      def top(self):
          if self.isempty():
              print('empty stack')
              return
  
          return self.top.data
      def printstack(self):
          if self.isempty():
              return
          temp = self.top
          print('stack from top')
          while temp != None:
              print(temp.data)
              temp = temp.next
  
  llist = linkedList()
  llist.push(5)
  llist.push(7)
  llist.push(9)
  llist.push(11)
  llist.push(13)
  llist.push(15)
  llist.push(17)
  llist.pop()
  llist.pop()
  llist.top()
  llist.pop()
  llist.push('oolala')
  llist.printstack()
  </code></pre>
  
  <p>But I'm getting the following error:</p>
  
  <pre><code>TypeError                                 Traceback (most recent call last)
  
  &lt;ipython-input-16-a71ab451bb35&gt; in &lt;module&gt;
       47 llist.pop()
       48 llist.pop()
  ---&gt; 49 llist.top()
       50 llist.pop()
       51 llist.push('oolala')
  
  TypeError: 'Node' object is not callable
  </code></pre>
  
  <p>How do I fix this?</p>