Merge Elixir keyword lists and maps

merge_keyword_lists_and_maps.ex

defp combine(list1, list2) do
  Keyword.merge(keyword_list(list1), keyword_list(list2), fn _k, _v1, v2 ->
    v2
  end)
end

def keyword_pair({key, value}) when is_atom(key) do
  {key, value}
end
def keyword_pair({key, value}) do
  {String.to_atom(key), value}
end

defp keyword_list(map) when is_map(map) do
  Enum.map(map, &__MODULE__.keyword_pair/1)
end
defp keyword_list(list), do: list