fixed ruby

irb(main):001:0> class Array
irb(main):002:1> def filter(&block)
irb(main):003:2> self.select(&block)
irb(main):004:2> end
irb(main):005:1> end
=> :filter
irb(main):006:0> [1, 2, 3].filter(&:even?)
=> [2]