method_missing (ActiveSupport::Multibyte::Chars)

    # File lib/active_support/multibyte/chars.rb, line 95
          def method_missing(method, *args, &block)
            if method.to_s =~ /!$/
              @wrapped_string.__send__(method, *args, &block)
              self
            else
              result = @wrapped_string.__send__(method, *args, &block)
              result.kind_of?(String) ? chars(result) : result
            end
          end