Fibonacci module for Elixir

fibonacci.ex

defmodule Fibonacci do
    @moduledoc """
    A Fibonacci series generator.
    """
    
    @doc """
    get_series/1 function.

    Returns a Fibonacci series in a list.

    ## Example

        iex> Fibonacci.get_series(11)
        [1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]

    """
    def get_series(qty) when qty > 0 do
        Stream.unfold({1, 1},
            fn {prev, current} ->  {prev, {current, prev + current}} end)
            |> Enum.take(qty)
    end

    def get_series(qty) when qty <= 0 do
        0
    end
end