I have below code:

class Node
  attr_accessor :val, :left, :right

  def initialize(val, l , r )
    @val =  val
    @left = l
    @right = r
  end

end



morse = Node.new(nil,
  Node.new ('E',
    Node.new ('I',
      Node.new ('S',
        Node.new ('H', 5 , 4),
        Node.new ('V', nil, 3)
        ),
      Node.new ('U',
        Node.new ('F', nil, ''),
        Node.new (18, nil, 2)
        )
      ),
    Node.new ('A',
      Node.new ('R',
        Node.new ('L', nil, ''),
        Node.new ('', nil, nil)
        ),
      Node.new ('W',
        Node.new ('P', nil, nil),
        Node.new ('J', 1, nil)
        )
      )
    )
  ,
  Node.new ('T',
    Node.new ('N',
      Node.new ('D',
        Node.new ('B', 6 , nil),
        Node.new ('X', nil, nil)
        ),
      Node.new ('K',
        Node.new ('C', '', nil),
        Node.new ('Y', nil, nil)
        )
      ),
    Node.new ('M',
      Node.new ('G',
        Node.new ('Z', '', nil),
        Node.new ('Q', '', nil)
        ),
      Node.new ('O',
        Node.new ('', 8, nil),
        Node.new ('H', 9, 0)
        )
      )
    )
)

Interpreter told me :
2.rb:14: syntax error, unexpected tLPAREN_ARG, expecting ')'
morse =  Node.new(nil, Node.new ('E', Node.new ('I',
                                 ^
2.rb:14: syntax error, unexpected ',', expecting ')'
morse =  Node.new(nil, Node.new ('E', Node.new ('I',
                                     ^
2.rb:14: syntax error, unexpected ',', expecting ')'
morse =  Node.new(nil, Node.new ('E', Node.new ('I',
                                                    ^
2.rb:15: syntax error, unexpected ',', expecting ')'
      Node.new ('S',
                    ^
2.rb:16: syntax error, unexpected ',', expecting ')'
        Node.new ('H', 5 , 4),
                      ^
wojciech@suse:~/ruby> ruby 2.rb
2.rb:15: syntax error, unexpected ',', expecting ')'
,Node.new ('E',
 ^
2.rb:15: syntax error, unexpected ',', expecting ')'
2.rb:16: syntax error, unexpected ',', expecting ')'
    Node.new ('I',
                  ^
2.rb:17: syntax error, unexpected ',', expecting ')'
      Node.new ('S',
                    ^
2.rb:18: syntax error, unexpected ',', expecting ')'
        Node.new ('H', 5 , 4),
                      ^

I don't know, what I do wrong.