diff --git a/lib/ex_aws/dynamo.ex b/lib/ex_aws/dynamo.ex
index 3b20897..82d6f62 100644
--- a/lib/ex_aws/dynamo.ex
+++ b/lib/ex_aws/dynamo.ex
@@ -309,7 +309,7 @@ defmodule ExAws.Dynamo do
   end
 
   @spec maybe_convert_billing_mode(attributes :: Keyword.t() | Map.t()) :: Keyword.t() | Map.t()
-  def maybe_convert_billing_mode(attributes) do
+  defp maybe_convert_billing_mode(attributes) do
     case attributes[:billing_mode] do
       nil -> attributes
       _   -> convert_billing_mode(attributes, attributes[:billing_mode])
@@ -317,13 +317,13 @@ defmodule ExAws.Dynamo do
   end
 
   @spec convert_billing_mode(attributes :: Keyword.t() | Map.t(), dynamo_billing_types) :: Keyword.t() | Map.t()
-  defp convert_billing_mode(attributes, :provisioned), do: do_convert(attributes, "PROVISIONED")
-  defp convert_billing_mode(attributes, :pay_per_request), do: do_convert(attributes, "PAY_PER_REQUEST")
+  defp convert_billing_mode(attributes, :provisioned), do: do_convert_billing_mode(attributes, "PROVISIONED")
+  defp convert_billing_mode(attributes, :pay_per_request), do: do_convert_billing_mode(attributes, "PAY_PER_REQUEST")
 
-  @spec do_convert(attributes :: Keyword.t() | Map.t(), value :: String.t()) :: Keyword.t() | Map.t()
-  defp do_convert(attributes, value) when is_map(attributes),
+  @spec do_convert_billing_mode(attributes :: Keyword.t() | Map.t(), value :: String.t()) :: Keyword.t() | Map.t()
+  defp do_convert_billing_mode(attributes, value) when is_map(attributes),
     do: Map.replace!(attributes, :billing_mode, value)
-  defp do_convert(attributes, value),
+  defp do_convert_billing_mode(attributes, value) when is_list(attributes),
     do: Keyword.replace!(attributes, :billing_mode, value)
 
   @doc "Delete Table"
diff --git a/test/lib/dynamo_test.exs b/test/lib/dynamo_test.exs
index 5e0ef81..c4710ed 100644
--- a/test/lib/dynamo_test.exs
+++ b/test/lib/dynamo_test.exs
@@ -118,11 +118,11 @@ defmodule ExAws.DynamoTest do
 
     assert Dynamo.update_table(
              "TestUsers",
-             [provisioned_throughput:
-               [read_capacity_units: 1,
-                write_capacity_units: 1],
+             %{provisioned_throughput:
+               %{read_capacity_units: 1,
+                write_capacity_units: 1},
               billing_mode: :provisioned
-             ]).data == expected
+             }).data == expected
 
     expected = %{
       "ProvisionedThroughput" => %{