# File lib/vcr.rb, line 50
  def insert_cassette(name, options = {})
    if turned_on?
      if cassettes.any? { |c| c.name == name }
        raise ArgumentError.new("There is already a cassette with the same name (#{name}).  You cannot nest multiple cassettes with the same name.")
      end

      cassette = Cassette.new(name, options)
      cassettes.push(cassette)
      cassette
    elsif !ignore_cassettes?
      message = "VCR is turned off.  You must turn it on before you can insert a cassette.  " +
                "Or you can use the `:ignore_cassette => true` option to completely ignore cassette insertions."
      raise TurnedOffError.new(message)
    end
  end