   """
   @spec drop(t, [key]) :: t
   def drop(keywords, keys) when is_list(keywords) and is_list(keys) do
-    :lists.filter(fn {key, _} -> key not in keys end, keywords)
+    :lists.filter(fn {k, _} -> k not in keys end, keywords)
   end
 
   @doc """

      ...>   {current_value, "new value!"}
      ...> end)
      {nil, [b: "new value!", a: 1]}

      iex> Keyword.get_and_update([a: 1], :a, fn _ -> :pop end)
      {1, []}

  @doc """
  Merges two keyword lists into one.

  All keys, including duplicate keys, given in `keywords2` will be added
  to `keywords1`. The given function will be invoked to solve conflicts.

  If `keywords2` has duplicate keys, the given function will be invoked
  for each matching pair in `keywords1`.

  There are no guarantees about the order of the keys in the returned keyword.

  ## Examples

