diff --git a/lib/paper_trail.ex b/lib/paper_trail.ex
index 41b99e37..b578b8d6 100644
--- a/lib/paper_trail.ex
+++ b/lib/paper_trail.ex
@@ -114,7 +114,10 @@ defmodule PaperTrail do
     |> model_or_error(:delete)
   end
 
-  @spec model_or_error(result :: {:ok, %{model: model}}, action :: :insert | :update | :delete) ::
+  @spec model_or_error(
+          result :: {:ok, %{required(:model) => model, optional(any()) => any()}},
+          action :: :insert | :update | :delete
+        ) ::
           model
         when model: struct()
   defp model_or_error({:ok, %{model: model}}, _action) do
diff --git a/lib/version.ex b/lib/version.ex
index b10e9c1d..0f18aacc 100644
--- a/lib/version.ex
+++ b/lib/version.ex
@@ -41,7 +41,7 @@ defmodule PaperTrail.Version do
     )
   end
 
-  def changeset(model, params \\ :empty) do
+  def changeset(model, params \\ %{}) do
     model
     |> cast(params, [:item_type, :item_id, :item_changes, :origin, :originator_id, :meta])
     |> validate_required([:event, :item_type, :item_id, :item_changes])