diff --git a/DTLib.Dtsod/ClassSerializer/DtsodAttributes.cs b/DTLib.Dtsod/ClassSerializer/DtsodAttributes.cs
new file mode 100644
index 0000000..e870b1c
--- /dev/null
+++ b/DTLib.Dtsod/ClassSerializer/DtsodAttributes.cs
@@ -0,0 +1,41 @@
+using System.Xml.Serialization;
+
+namespace DTLib.Dtsod;
+
+[AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Interface)]
+public class DtsodSerializableAttribute : Attribute
+{
+    public DtsodVersion Version;
+    public DtsodSerializableAttribute(DtsodVersion ver) => Version = ver;
+}
+
+
+[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property)]
+public class SerializeAsAttribute: Attribute
+{
+    public string Key;
+    /// <summary>
+    /// use it only for base types
+    /// </summary>
+    /// <param name="key">name the field will be serialized as</param>
+    public SerializeAsAttribute(string key) => Key = key;
+}
+
+[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property)]
+public class SerializationMethodAttribute<TSource,TSerialized> : Attribute
+{
+    public Func<TSource, TSerialized> Method;
+    /// <summary>
+    /// </summary>
+    /// <param name="method">how to serialize field</param>
+    public SerializationMethodAttribute(Func<TSource, TSerialized> method) => Method = method;
+}
+[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property)]
+public class DeserializationMethodAttribute<TSource,TSerialized> : Attribute
+{
+    public Func<TSerialized, TSource> Method;
+    /// <summary>
+    /// </summary>
+    /// <param name="method">how to deserialize field</param>
+    public DeserializationMethodAttribute( Func<TSerialized, TSource> method) => Method = method;
+}
\ No newline at end of file
diff --git a/DTLib.Dtsod/Dependencies/windows/x64/kerep.dll b/DTLib.Dtsod/Dependencies/windows/x64/kerep.dll
index 0aff218..2286c23 100644
Binary files a/DTLib.Dtsod/Dependencies/windows/x64/kerep.dll and b/DTLib.Dtsod/Dependencies/windows/x64/kerep.dll differ
diff --git a/DTLib.Dtsod/Dependencies/windows/x86/kerep.dll b/DTLib.Dtsod/Dependencies/windows/x86/kerep.dll
index b5a30f8..109371d 100644
Binary files a/DTLib.Dtsod/Dependencies/windows/x86/kerep.dll and b/DTLib.Dtsod/Dependencies/windows/x86/kerep.dll differ
diff --git a/DTLib.Dtsod/DtsodV23.cs b/DTLib.Dtsod/DtsodV23.cs
index e9e32fd..29cacda 100644
--- a/DTLib.Dtsod/DtsodV23.cs
+++ b/DTLib.Dtsod/DtsodV23.cs
@@ -151,7 +151,9 @@ public class DtsodV23 : DtsodDict<string, dynamic>, IDtsod
                 List<dynamic> list = new();
                 while (true)
                 {
-                    list.Add(ReadValue(out bool _eol));
+                    var item = ReadValue(out bool _eol);
+                    if(item!=null)
+                        list.Add(item);
                     if (_eol) break;
                 }
 
@@ -239,6 +241,12 @@ public class DtsodV23 : DtsodDict<string, dynamic>, IDtsod
                         break;
                     case ';':
                     case ',':
+                        if(b.Length == 0)
+                        {
+                            if(endOfList)
+                                return null;
+                            throw new Exception("zero length value");
+                        }
                         string str = b.ToString();
                         b.Clear();
                         return ParseValue(str);
@@ -287,42 +295,54 @@ public class DtsodV23 : DtsodDict<string, dynamic>, IDtsod
         { typeof(double), (val, b) => b.Append(val.ToString(CultureInfo.InvariantCulture)) },
         { typeof(decimal), (val, b) => b.Append(val.ToString(CultureInfo.InvariantCulture)).Append("de") }
     };
-    short tabscount = -1;
-    protected StringBuilder Serialize(DtsodV23 dtsod, StringBuilder b = null)
-    {
+    
+    protected StringBuilder Serialize(DtsodV23 dtsod, ref int tabscount, StringBuilder b = null)
+    {;
         tabscount++;
         if (b is null) b = new StringBuilder();
         foreach (var pair in dtsod)
         {
             b.Append('\t', tabscount).Append(pair.Key).Append(": ");
-            SerializeType(pair.Value);
+            SerializeType(pair.Value, ref tabscount);
             b.Append(";\n");
 
-            void SerializeType(dynamic value)
+            void SerializeType(dynamic value, ref int tabscount)
             {
                 if (value is null) b.Append("null");
+                else if (value is DtsodV23 _dtsod)
+                {
+                    b.Append("{\n");
+                    Serialize(_dtsod, ref tabscount, b);
+                    b.Append('}');
+                }
                 else if (value is IList _list)
                 {
                     b.Append('[');
                     foreach (object el in _list)
                     {
-                        SerializeType(el);
+                        SerializeType(el, ref tabscount);
                         b.Append(',');
                     }
                     b.Remove(b.Length - 1, 1).Append(']');
                 }
-                else if (value is DtsodV23 _dtsod)
-                {
-                    b.Append("{\n");
-                    Serialize(_dtsod, b);
-                    b.Append('}');
-                }
                 else TypeSerializeFuncs[value.GetType()].Invoke(value, b);
             }
         }
         tabscount--;
         return b;
     }
-    
-    public override string ToString() => Serialize(this).ToString();
+
+    public override string ToString()
+    {
+        int tabscount = -1;
+        return Serialize(this, ref tabscount).ToString();
+    }
+
+    ///serializes dtsod as part of list
+    public string ToString(string partialListName) 
+    {
+        int tabscount = 0;
+        var builder = new StringBuilder().Append('$').Append(partialListName).Append(":\n{\n");
+        return Serialize(this, ref tabscount, builder).Append("};\n").ToString();
+    }
 }
diff --git a/DTLib.Dtsod/V30/DtsodSerializableAttribute.cs b/DTLib.Dtsod/V30/DtsodSerializableAttribute.cs
deleted file mode 100644
index 9d3fe10..0000000
--- a/DTLib.Dtsod/V30/DtsodSerializableAttribute.cs
+++ /dev/null
@@ -1,7 +0,0 @@
-namespace DTLib.Dtsod;
-
-public class DtsodSerializableAttribute : Attribute
-{
-    public DtsodVersion Version;
-    public DtsodSerializableAttribute(DtsodVersion ver) => Version = ver;
-}
diff --git a/DTLib/Extensions/Collections.cs b/DTLib/Extensions/Collections.cs
index f189203..ec7f5cc 100644
--- a/DTLib/Extensions/Collections.cs
+++ b/DTLib/Extensions/Collections.cs
@@ -2,37 +2,9 @@
 
 public static class Collections
 {
-
     public static void ForEach<T>(this IEnumerable<T> en, Action<T> act)
     {
         foreach (T elem in en)
             act(elem);
     }
-
-    // массив в лист
-    public static List<T> ToList<T>(this T[] input)
-    {
-        var list = new List<T>();
-        list.AddRange(input);
-        return list;
-    }
-
-    // удаление нескольких элементов массива
-    public static T[] RemoveRange<T>(this T[] input, int startIndex, int count)
-    {
-        var list = input.ToList();
-        list.RemoveRange(startIndex, count);
-        return list.ToArray();
-    }
-    public static T[] RemoveRange<T>(this T[] input, int startIndex) => input.RemoveRange(startIndex, input.Length - startIndex);
-
-
-    // метод как у листов
-    public static bool Contains<T>(this T[] array, T value)
-    {
-        for (int i = 0; i < array.Length; i++)
-            if (array[i].Equals(value))
-                return true;
-        return false;
-    }
 }
diff --git a/DTLib/Extensions/StringConverter.cs b/DTLib/Extensions/StringConverter.cs
index b849962..70ed1c1 100644
--- a/DTLib/Extensions/StringConverter.cs
+++ b/DTLib/Extensions/StringConverter.cs
@@ -144,4 +144,6 @@ public static class StringConverter
         if (max * length != s.Length) parts.Add(s.Substring(max * length, s.Length - max * length));
         return parts;
     }
+
+    public static bool IsNullOrEmpty(this string s) => String.IsNullOrEmpty(s);
 }