编写 Ruby 类方法并收到意外的令牌 kEND 错误

问：

我正在写一个类，并给它一个类方法。我收到错误。我一直在盯着代码，看不出错误可能在哪里。我想我已经把我所有的都准备好了。我错过了什么？Wrapperself.wrapunexpected end-of-inputend

require 'pry'
class Wrapper
    def self.wrap(input_string, column_number)
        position = 0
        num_inserted = 0
        while (position + column_number < line.length) do
            last_space_index = input_string.rindex(" ", position + column_number)
            if last_space_index > position - 1
                input_string[num_inserted + last_space_index] = "\n"
            else
                input_string.insert(num_inserted + position + column_number, "\n")
                position += column_number
                num_inserted ++
            end
        end
    end
end