diff --git a/python/obitools3/utils.pxd b/python/obitools3/utils.pxd
index 0673af4..5360f95 100644
--- a/python/obitools3/utils.pxd
+++ b/python/obitools3/utils.pxd
@@ -8,6 +8,10 @@ cdef bytes str2bytes(str string)
 cdef str bytes2str(bytes string)
 cdef bytes tobytes(object string)
 cdef str tostr(object string)
+cdef object bytes2str_object(object value)
+cdef object str2bytes_object(object value)
+
+cdef object clean_empty_values_from_object(object value, exclude=*)
 
 cdef obitype_t get_obitype_single_value(object value)
 cdef obitype_t update_obitype(obitype_t obitype, object new_value)
diff --git a/python/obitools3/utils.pyx b/python/obitools3/utils.pyx
index d75225b..319501b 100644
--- a/python/obitools3/utils.pyx
+++ b/python/obitools3/utils.pyx
@@ -87,6 +87,70 @@ cdef str tostr(object string):
     return bytes2str(string)
 
 
+cdef object bytes2str_object(object value):  # Only works if complex types are dict or list
+    if isinstance(value, dict):
+        items = [(k,v) for k,v in value.items()]
+        for k, v in items:
+            if isinstance(v, list) or isinstance(v, dict):
+                value[k] = bytes2str_object(v)
+            else:
+                if type(v) == bytes:
+                    value[k] = bytes2str(v)
+            if type(k) == bytes:
+                value[bytes2str(k)] = value.pop(k)
+    elif isinstance(value, list):
+        for i in range(len(value)):
+            if isinstance(value[i], list) or isinstance(value[i], dict):
+                value[i] = bytes2str_object(value[i])
+            if type(value[i]) == bytes:
+                value[i] = bytes2str(value[i])
+    elif type(value) == bytes:
+        value = bytes2str(value)
+    return value
+
+
+cdef object str2bytes_object(object value):  # Only works if complex types are dict or list
+    if isinstance(value, dict):
+        items = [(k,v) for k,v in value.items()]
+        for k, v in items:
+            if isinstance(v, list) or isinstance(v, dict):
+                value[k] = str2bytes_object(v)
+            else:
+                if type(v) == str:
+                    value[k] = str2bytes(v)
+            if type(k) == str:
+                value[str2bytes(k)] = value.pop(k)
+    elif isinstance(value, list):
+        for i in range(len(value)):
+            if isinstance(value[i], list) or isinstance(value[i], dict):
+                value[i] = str2bytes_object(value[i])
+            if type(value[i]) == str:
+                value[i] = str2bytes(value[i])
+    elif type(value) == str:
+        value = str2bytes(value)
+    return value
+
+
+cdef object clean_empty_values_from_object(object value, exclude=[]):    # Only works if complex types are dict or list
+    if isinstance(value, dict):
+        items = [(k,v) for k,v in value.items()]
+        for k, v in items:
+            if isinstance(v, list) or isinstance(v, dict):
+                value[k] = clean_empty_values_from_object(v)
+            if (k not in exclude) and (v is None or (hasattr(v, '__len__') and len(v) == 0)):
+                value.pop(k)
+    elif isinstance(value, list):
+        to_remove=[]
+        for i in range(len(value)):
+            if isinstance(value[i], list) or isinstance(value[i], dict):
+                value[i] = clean_empty_values_from_object(value[i])
+            if value[i] is None or (hasattr(value[i], '__len__') and len(value[i]) == 0):
+                to_remove.append(value[i])
+        for v in to_remove:
+            value.remove(v)
+    return value
+
+
 cdef obitype_t get_obitype_single_value(object value) :
 
     cdef type       value_type