fix linting

lib/mv/membership/member_export/build.ex

@@ -272,24 +272,34 @@ defmodule Mv.Membership.MemberExport.Build do
     if field == "groups" do
       sort_members_by_groups_export(members, order)
     else
-      id_str = String.trim_leading(field, @custom_field_prefix)
-      custom_field = Enum.find(custom_fields, fn cf -> to_string(cf.id) == id_str end)
-
-      if is_nil(custom_field), do: members
-
-      key_fn = fn member ->
-        cfv = find_cfv(member, custom_field)
-        raw = if cfv, do: cfv.value, else: nil
-        MemberExportSort.custom_field_sort_key(custom_field.value_type, raw)
-      end
-
-      members
-      |> Enum.map(fn m -> {m, key_fn.(m)} end)
-      |> Enum.sort(fn {_, ka}, {_, kb} -> MemberExportSort.key_lt(ka, kb, order) end)
-      |> Enum.map(fn {m, _} -> m end)
+      sort_by_custom_field_value(members, field, order, custom_fields)
     end
   end
 
+  defp sort_by_custom_field_value(members, field, order, custom_fields) do
+    id_str = String.trim_leading(field, @custom_field_prefix)
+    custom_field = Enum.find(custom_fields, fn cf -> to_string(cf.id) == id_str end)
+
+    if is_nil(custom_field) do
+      members
+    else
+      sort_members_with_custom_field(members, custom_field, order)
+    end
+  end
+
+  defp sort_members_with_custom_field(members, custom_field, order) do
+    key_fn = fn member ->
+      cfv = find_cfv(member, custom_field)
+      raw = if cfv, do: cfv.value, else: nil
+      MemberExportSort.custom_field_sort_key(custom_field.value_type, raw)
+    end
+
+    members
+    |> Enum.map(fn m -> {m, key_fn.(m)} end)
+    |> Enum.sort(fn {_, ka}, {_, kb} -> MemberExportSort.key_lt(ka, kb, order) end)
+    |> Enum.map(fn {m, _} -> m end)
+  end
+
   defp sort_members_by_groups_export(members, order) do
     # Members with groups first, then by first group name alphabetically (min = first by sort order)
     # Match table behavior from MvWeb.MemberLive.Index.sort_members_by_groups/2