class SimpleCov::Formatter::MultiFormatter

def self.new(formatters = nil)
  # Normalize eagerly and capture the list in the closure. Array()
  # is pure for every accepted input shape (nil, single formatter,
  # array, or another MultiFormatter class), so this is equivalent
  # to the historical lazy per-instance memoization.
  formatter_list = Array(formatters)
  Class.new do
    define_method :formatters do
      formatter_list
    end
    include InstanceMethods
  end
end