gistfile1.txt

class Foo

  def initialize(opts)
    @config ||= configure(opts)
  end
  
  private
  
  configure(opts)
    if opts.nil? || opts.empty?
      raise ArgumentError, 'Options argument cannot be nil or empty'
    end

    if opts.class == Hash
      config = {}
      opts.each do |k, v|
        config[k.to_sym] = v if valid_key?(k)
      end
    end

     config
  end
end