def to_s(groupsOf = 8)
      groupsOf = 8 if groupsOf == 0
      s = ""
      length.times do |i|
        s << (set?(i) ? "1" : "0")
        s << " " if i % groupsOf == 0
      end
      s
    end
def to_s(groupsOf = 8)
      groupsOf = 8 if groupsOf == 0
      s = ""
      length.times do |i|
        s << (set?(i) ? "1" : "0")
        s << " " if i % groupsOf == 0
      end
      s
    end
Return a display string representing the bitfield.