initial use UndefinedFunctionError

[ZachParsons]

After adding this dep to my mix.exs & runningmix deps.get which ran fine.

I added to my schema that has a parent_id field use Arbor.Tree, foreign_key_type: :binary_id belongs_to :parent, __MODULE__

On mix compile - this error:

** (UndefinedFunctionError) function nil.source/0 is undefined. If you are using the dot syntax, such as map.field or module.function(), make sure the left side of the dot is an atom or a map
    nil.source()
    (arbor 1.1.0) expanding macro: Arbor.Tree.__before_compile__/1