code: public static BtcFormat getMicroInstance(Locale locale, int scale, int... groups) {
          return getInstance(MICROCOIN_SCALE, locale, scale, boxAsList(groups));
      }
docs: Return a new microcoin-denominated formatter for the given locale with the specified
  fractional decimal placing.  The returned object will format the fractional part of
  numbers with the given minimum number of fractional decimal places.  Optionally,
  repeating integer arguments can be passed, each indicating the size of an additional
  group of fractional decimal places to be used as necessary to avoid rounding, to a
  limiting precision of satoshis.