class Generator
  def self.random(length=(3..7).to_a.sample)
    generate('?' * length)
  end

  def self.human(length=(3..7).to_a.sample)
    generate(('*#' * length).slice(rand(length), length))
  end

  def self.format(format)
    generate(format)
  end

  def self.generate(format)
    format.split('').map(&:namna_sub).join('')
  end
end