diff --git a/base_jsonify/models/models.py b/base_jsonify/models/models.py
index a26d23a52..226f771ab 100644
--- a/base_jsonify/models/models.py
+++ b/base_jsonify/models/models.py
@@ -62,9 +62,7 @@ class Base(models.AbstractModel):
     @api.model
     def _add_json_key(self, values, json_key, value):
         """To manage defaults, you can use a specific resolver."""
-        key_marshaller = json_key.split("=")
-        key = key_marshaller[0]
-        marshaller = key_marshaller[1] if len(key_marshaller) > 1 else None
+        key, sep, marshaller = json_key.partition("=")
         if marshaller == "list":  # sublist field
             if not values.get(key):
                 values[key] = []
@@ -170,7 +168,8 @@ class Base(models.AbstractModel):
             for record, json in zip(records, results):
                 self._jsonify_record(parsers[lang], record, json)
 
-        results = resolver.resolve(results, self) if resolver else results
+        if resolver:
+            results = resolver.resolve(results, self)
         return results[0] if one else results
 
     # HELPERS
diff --git a/base_jsonify/models/utils.py b/base_jsonify/models/utils.py
index 150f3f809..dba45cc06 100644
--- a/base_jsonify/models/utils.py
+++ b/base_jsonify/models/utils.py
@@ -4,14 +4,14 @@ def convert_simple_to_full_parser(parser):
     return {"fields": _convert_parser(parser)}
 
 
-def _f(f, function=None):
+def _convert_field(fld, function=None):
     """Return a dict from the string encoding a field to export.
     The : is used as a separator to specify a target, if any.
     """
-    field_split = f.split(":")
-    field_dict = {"name": field_split[0]}
-    if len(field_split) > 1:
-        field_dict["target"] = field_split[1]
+    name, sep, target = fld.partition(":")
+    field_dict = {"name": name}
+    if target:
+        field_dict["target"] = target
     if function:
         field_dict["function"] = function
     return field_dict
@@ -24,11 +24,12 @@ def _convert_parser(parser):
     result = []
     for line in parser:
         if isinstance(line, str):
-            result.append(_f(line))
+            field_def = _convert_field(line)
         else:
-            f, sub = line
+            fld, sub = line
             if callable(sub) or isinstance(sub, str):
-                result.append(_f(f, sub))
+                field_def = _convert_field(fld, sub)
             else:
-                result.append((_f(f), _convert_parser(sub)))
+                field_def = (_convert_field(fld), _convert_parser(sub))
+        result.append(field_def)
     return result