def map_vectors!
      return to_enum(:map_vectors!) unless block_given?

      vectors.dup.each do |n|
        self[n] = should_be_vector!(yield(self[n]))
      end

      self
    end
def map_vectors!
      return to_enum(:map_vectors!) unless block_given?

      vectors.dup.each do |n|
        self[n] = should_be_vector!(yield(self[n]))
      end

      self
    end
Destructive form of #map_vectors