def invert
      build(precision: precision, deg: (deg + 180) % 360, suffix: SUFFIX_INVERSIONS.fetch(suffix, suffix))
    end
def invert
      build(precision: precision, deg: (deg + 180) % 360, suffix: SUFFIX_INVERSIONS.fetch(suffix, suffix))
    end
Invert an angle by 180 degrees

 @example
   AIXM.a(120).invert     # => AIXM.a(300)
   AIXM.a("34L").invert   # => AIXM.a("16R")
   AIXM.a("33X").invert   # => AIXM.a("33X")

 @return [AIXM::A] inverted angle