    # File lib/action_mailer/vendor/tmail-1.2.3/tmail/utils.rb, line 228
        def timezone_string_to_unixtime( str )
          if m = /([\+\-])(\d\d?)(\d\d)/.match(str)
            sec = (m[2].to_i * 60 + m[3].to_i) * 60
            m[1] == '-' ? -sec : sec
          else
            min = ZONESTR_TABLE[str.downcase] or
                    raise SyntaxError, "wrong timezone format '#{str}'"
            min * 60
          end
        end