Transformer encoder

combo/config/from_parameters.py

 import functools
 import inspect
 import typing
+from types import NoneType
 from typing import Any, Callable, Dict, List, Optional
 
 from combo.common.params import Params
@@ -58,6 +59,8 @@ def serialize_single_value(value: Any, pass_down_parameter_names: List[str] = No
         return {k: serialize_single_value(v, pass_down_parameter_names) for k, v in value.items()}
     elif isinstance(value, int) or isinstance(value, float) or isinstance(value, str):
         return value
+    elif isinstance(value, NoneType):
+        return None
     else:
         return str(value)
 
@@ -145,6 +148,8 @@ class FromParameters:
 
         parameters_dict = {}
         for pn, param_value in parameters_to_serialize.items():
+            if pn == 'seq_encoder':
+                a = 0
             if pn in pass_down_parameter_names:
                 continue
             parameters_dict[pn] = serialize_single_value(param_value,