unquote_and_convert_to (TMail::Unquoter)

    # File lib/action_mailer/vendor/tmail/quoting.rb, line 50
          def unquote_and_convert_to(text, to_charset, from_charset = "iso-8859-1", preserve_underscores=false)
            return "" if text.nil?
            if text =~ /^=\?(.*?)\?(.)\?(.*)\?=$/
              from_charset = $1
              quoting_method = $2
              text = $3
              case quoting_method.upcase
                when "Q" then
                  unquote_quoted_printable_and_convert_to(text, to_charset, from_charset, preserve_underscores)
                when "B" then
                  unquote_base64_and_convert_to(text, to_charset, from_charset)
                else
                  raise "unknown quoting method #{quoting_method.inspect}"
              end
            else
              convert_to(text, to_charset, from_charset)
            end
          end