oh why?

>> def fz(names)
>>   names.each do
?>       |name|
?>       yield File.open name, 'r'
>>     end
>>   end
=> nil
>> f = ['d2', 'd3']
=> ["d2", "d3"]
>> files = fz f
LocalJumpError: no block given (yield)
        from (irb):261:in `block in fz'
        from (irb):259:in `each'
        from (irb):259:in `fz'
        from (irb):265
        from /usr/bin/irb:12:in `<main>'