input: 
  def isSubTree(T: Node, S: Node) -> bool:
      """ Check if tree S is a subtree of tree T.
      >>> T = Node(26)
      >>> T.left = Node(10)
      >>> T.right = Node(3)
      >>> T.left.left = Node(4)
      >>> T.left.right = Node(6)
      >>> T.right.right = Node(3)
      >>> T.left.left.right = Node(30)
      >>> S = Node(10)
      >>> S.left = Node(4)
      >>> S.right = Node(6)
      >>> S.left.right = Node(30)
      >>> isSubTree(T, S)
      False
      """
  
      if S is None: 
          return True
    
      if T is None: 
          return False
    
      if areIdentical(T, S): 
          return True
    
      return isSubTree(T.left, S) or isSubTree(T.right, S) 
    
    
  def areIdentical(T, S): 
        
      if T is None and S is None: 
          return True
    
      if T is None or S is None: 
          return False
    
      return (T.data == S.data and areIdentical(T.left, S.left)and
          areIdentical(T.right, S.right))
  
output:     def isSubTree(T: Node, S: Node) -> bool:
          """ Check if tree S is a subtree of tree T.
          >>> T = Node(26)
          >>> T.left = Node(10)
          >>> T.right = Node(3)
          >>> T.left.left = Node(4)
          >>> T.left.right = Node(6)
          >>> T.right.right = Node(3)
          >>> T.left.left.right = Node(30)
          >>> S = Node(10)
          >>> S.left = Node(4)
          >>> S.right = Node(6)
          >>> S.left.right = Node(30)
          >>> isSubTree(T, S)
          False
          """
      
          if S is None: 
              return True
        
          if T is None: 
              return False
        
          if areIdentical(T, S): 
              return True
        
          return isSubTree(T.left, S) or isSubTree(T.right, S) 
        
        
      def areIdentical(T, S): 
            
          if T is None and S is None: 
              return True
        
          if T is None or S is None: 
              return False
        
          return (T.data == S.data and areIdentical(T.left, S.left)and
              areIdentical(T.right, S.right))