diff --git a/lib/ukraine_taxid_ex/edrpou/check_sum.ex b/lib/ukraine_taxid_ex/edrpou/check_sum.ex
index 1c116fa..bb4e28b 100644
--- a/lib/ukraine_taxid_ex/edrpou/check_sum.ex
+++ b/lib/ukraine_taxid_ex/edrpou/check_sum.ex
@@ -36,16 +36,39 @@ defmodule UkraineTaxidEx.Edrpou.CheckSum do
 
   defguardp is_base_weights(value) when value < 30_000_000 or value > 60_000_000
 
-  @spec weights(type :: weights_type, double_added? :: boolean()) :: C.digits()
-  defp weights(type \\ :base, double_added \\ false)
-  defp weights(:base, false), do: Enum.to_list(1..7)
+  @doc """
+    Returns a list of weights used for EDRPOU check sum calculation.
+    When double_added is true, adds 2 to each weight in the list.
 
-  defp weights(:alternative, false) do
+    ## Parameters
+      - type: `:base` or `:alternative` weights pattern
+      - double_added: when true, adds 2 to each weight
+
+    ## Examples
+    ```elixir
+        iex> weights(:base)
+        [1, 2, 3, 4, 5, 6, 7]
+
+        iex> weights(:alternative)
+        [7, 1, 2, 3, 4, 5, 6]
+
+        iex> weights(:base, true)
+        [3, 4, 5, 6, 7, 8, 9]
+
+        iex> weights(:alternative, true)
+        [9, 3, 4, 5, 6, 7, 8]
+    ```
+  """
+  @spec weights(type :: weights_type, double_added? :: boolean()) :: C.digits()
+  def weights(type \\ :base, double_added \\ false)
+  def weights(:base, false), do: Enum.to_list(1..7)
+
+  def weights(:alternative, false) do
     base = weights()
     [List.last(base) | Enum.take(base, length(base) - 1)]
   end
 
-  defp weights(type, true) do
+  def weights(type, true) do
     type
     |> weights(false)
     |> Enum.map(&(&1 + 2))
diff --git a/lib/ukraine_taxid_ex/edrpou/parser.ex b/lib/ukraine_taxid_ex/edrpou/parser.ex
index 5d80059..d597a5c 100644
--- a/lib/ukraine_taxid_ex/edrpou/parser.ex
+++ b/lib/ukraine_taxid_ex/edrpou/parser.ex
@@ -21,13 +21,12 @@ defmodule UkraineTaxidEx.Edrpou.Parser do
           | {:error,
              :length_too_short
              | :length_too_long
-             | :invalid_length
              | :invalid_checksum}
 
   @impl BaseParser
 
   @doc """
-  Parses an EDRPOU code string into a structured format.
+  Parses an EDRPOU code string into a structured format (clean and normalize, validate and decompose).
   Options:
   - normalize?: When true, pads string to full EDRPOU length. Defaults to false.
   - clean?: When true, removes non-digit characters before processing. Defaults to false.
diff --git a/test/ukraine_taxid_ex/edrpou/check_sum_test.exs b/test/ukraine_taxid_ex/edrpou/check_sum_test.exs
index 689e79e..20d5672 100644
--- a/test/ukraine_taxid_ex/edrpou/check_sum_test.exs
+++ b/test/ukraine_taxid_ex/edrpou/check_sum_test.exs
@@ -1,6 +1,29 @@
 defmodule UkraineTaxidEx.Edrpou.CheckSumTest do
   use ExUnit.Case
   alias UkraineTaxidEx.Edrpou.CheckSum
+  doctest UkraineTaxidEx.Edrpou.Parser
+
+  describe "weights/2" do
+    test "returns base weights by default" do
+      assert CheckSum.weights() == [1, 2, 3, 4, 5, 6, 7]
+    end
+
+    test "returns base weights when not added 2" do
+      assert CheckSum.weights(:base, false) == [1, 2, 3, 4, 5, 6, 7]
+    end
+
+    test "returns alternative weights when added 2" do
+      assert CheckSum.weights(:alternative, false) == [7, 1, 2, 3, 4, 5, 6]
+    end
+
+    test "returns base weights + 2" do
+      assert CheckSum.weights(:base, true) == [3, 4, 5, 6, 7, 8, 9]
+    end
+
+    test "returns alternative weights + 2 " do
+      assert CheckSum.weights(:alternative, true) == [9, 3, 4, 5, 6, 7, 8]
+    end
+  end
 
   describe "check_sum/1" do
     test "calculates correct checksum for EDRPOU with base weights (< 30M) short EDRPOU with leading zeros" do
diff --git a/test/ukraine_taxid_ex/edrpou_test.exs b/test/ukraine_taxid_ex/edrpou_test.exs
index 4ff722f..9abbe55 100644
--- a/test/ukraine_taxid_ex/edrpou_test.exs
+++ b/test/ukraine_taxid_ex/edrpou_test.exs
@@ -1,26 +1,3 @@
 defmodule UkraineTaxidEx.EdrpouTest do
   use ExUnit.Case
-  # alias UkraineTaxidEx.Edrpou
-
-  # describe "weights/2" do
-  #   test "returns base weights by default" do
-  #     assert Edrpou.weights() == [1, 2, 3, 4, 5, 6, 7]
-  #   end
-
-  #   test "returns base weights when not doubled" do
-  #     assert Edrpou.weights(:base, false) == [1, 2, 3, 4, 5, 6, 7]
-  #   end
-
-  #   test "returns alternative weights when not doubled" do
-  #     assert Edrpou.weights(:alternative, false) == [7, 1, 2, 3, 4, 5, 6]
-  #   end
-
-  #   test "returns doubled base weights" do
-  #     assert Edrpou.weights(:base, true) == [2, 4, 6, 8, 10, 12, 14]
-  #   end
-
-  #   test "returns doubled alternative weights" do
-  #     assert Edrpou.weights(:alternative, true) == [14, 2, 4, 6, 8, 10, 12]
-  #   end
-  # end
 end