class Net::SSH::Transport::HMAC::Abstract

def mac_length(*v)
  @mac_length = nil if !defined?(@mac_length)
  if v.empty?
    @mac_length = superclass.mac_length if @mac_length.nil? && superclass.respond_to?(:mac_length)
    return @mac_length
  elsif v.length == 1
    @mac_length = v.first
  else
    raise ArgumentError, "wrong number of arguments (#{v.length} for 1)"
  end
end