fixes flatten

Author: ivaylo-matov

DSPythonNet3/Encoders/ListEncodeDecoder.cs

@@ -28,18 +28,18 @@ public bool TryDecode<T>(PyObject pyObj, out T value)
                 return false;
             }
 
-            using (var pyList = PyList.AsList(pyObj))
+            if (typeof(T).IsGenericType)
             {
-                if (typeof(T).IsGenericType)
+                using (var pyList = PyList.AsList(pyObj))
                 {
                     value = pyList.ToList<T>();
                 }
-                else
-                {
-                    value = (T)pyList.ToList();
-                }
                 return true;
             }
+
+            var converted = ConvertToArrayList(pyObj);
+            value = (T)converted;
+            return true;
         }
 
         public PyObject TryEncode(object value)
@@ -57,5 +57,53 @@ bool IPyObjectDecoder.CanDecode(PyType objectType, Type targetType)
             }
             return decodableTypes.IndexOf(targetType) >= 0;
         }
+
+        private static IList ConvertToArrayList(PyObject pyObj)
+        {
+            using var pyList = PyList.AsList(pyObj);
+            var result = new ArrayList();
+            foreach (PyObject item in pyList)
+            {
+                using (item)
+                {
+                    result.Add(ConvertItem(item));
+                }
+            }
+            return result;
+        }
+
+        private static object ConvertItem(PyObject item)
+        {
+            if (TryGetClrObject(item, out var clrObject))
+            {
+                return clrObject;
+            }
+
+            if (PyString.IsStringType(item))
+            {
+                return item.AsManagedObject(typeof(string));
+            }
+
+            if (PyList.IsListType(item) || PyTuple.IsTupleType(item))
+            {
+                return ConvertToArrayList(item);
+            }
+
+            return item.AsManagedObject(typeof(object));
+        }
+
+        private static bool TryGetClrObject(PyObject pyObj, out object clrObject)
+        {
+            try
+            {
+                clrObject = pyObj.GetManagedObject();
+                return clrObject != null;
+            }
+            catch
+            {
+                clrObject = null;
+                return false;
+            }
+        }
     }
 }