# File text/format.rb, line 315
315:     def hyphenator=(h)
316:       raise ArgumentError, "#{h.inspect} is not a valid hyphenator." unless h.respond_to?(:hyphenate_to)
317:       arity = h.method(:hyphenate_to).arity
318:       raise ArgumentError, "#{h.inspect} must have exactly two or three arguments." unless [2, 3].include?(arity)
319:       @hyphenator = h
320:       @hyphenator_arity = arity
321:     end