defmodule CurrencyConverter do
  @moduledoc """
  Documentation for `CurrencyConverter`.
  """

  @doc ~S"""
  Convert a list of currencies to Nigerian Naira (NGN)

  ## Examples

      iex> CurrencyConverter.to_ngn
      nil
      iex> CurrencyConverter.to_ngn([1,2,3,4,5])
      3.0

  """
  def to_ngn, do: nil
  def to_ngn(list) do
    Enum.sum(list) / Kernel.length(list)
  end
end