     do: Keyword.fetch(aliases, :"Elixir.#{atom}")
 
   @doc """
-  Returns the macro alias for the given atom, `nil` otherwise.
+  Fetches the macro alias for the given atom.
+
+  Returns `{:ok, macro_alias}` if the alias exists, `:error`
+  otherwise.
 
   A macro alias is only used inside quoted expansion. See
   `fetch_alias/2` for a more general example.

      do: Keyword.fetch(aliases, :"Elixir.#{atom}")

  @doc """
  Returns from which modules the given `{name, arity}` is
  imported from.

  It returns a list of two element tuples in the shape of
  `{:function | :macro, module}`. The elements in the list

  end

  @doc """
  Fetches the alias for the given atom.

  Returns `{:ok, alias}` if the alias exists, `:error` 
  otherwise.

  ## Examples

