Yeaaah! Nice, man. :)

Hey @gregziolo, sup? The documentation for the max_by method: http://ruby-doc.org/core-2.2.2/Enumerable.html#method-i-max_by

They get the max value from an Enumerable, in this case a list.

The &block is the block you pass as a parameter for the max_by. e.g

def max_by list, &block
  list.max_by(&block)
end

max_by ['hi', 'foo', 'bigger'] { |x| x.length }
# => 'bigger'

Any doubt, please reply! :D