Please review my Tags Unify module

I am back to learn Elixir, and I am building a pet project to help me with my developer notes and collection of links, and as part of it I need to have a unique tags system

My Solution:

A Test Example:

iex> tags = Utils.TagsUnify.test_tags_list()
    " elixir", 
    " My   Elixir Status", 
    "my     elixir    Status",
    " phoenix   framework ", 
    " phoenixframework", 
    " phoenix ", 
    "   ", 
    "   ",
    " Elixir ", 
    " My-Elixir-Status", 
    " my Elixir status", 
    " my elixir status", 
    " Elixir"

iex> tags |> Utils.TagsUnify.list()

Please feel free to suggest improvements, say If I missed something or that my approach is not the best way to go for it.