instance method update_with_single_argument

# File activesupport/lib/active_support/hash_with_indifferent_access.rb, line 406
      def update_with_single_argument(other_hash, block)
        if other_hash.is_a? HashWithIndifferentAccess
          regular_update(other_hash, &block)
        else
          other_hash.to_hash.each_pair do |key, value|
            if block && key?(key)
              value = block.call(convert_key(key), self[key], value)
            end
            regular_writer(convert_key(key), convert_value(value))
          end
        end
      end