diff --git a/report_xlsx_helper/readme/CONTRIBUTORS.rst b/report_xlsx_helper/readme/CONTRIBUTORS.rst
index 044d1a00..67f1fb2e 100644
--- a/report_xlsx_helper/readme/CONTRIBUTORS.rst
+++ b/report_xlsx_helper/readme/CONTRIBUTORS.rst
@@ -1 +1,2 @@
 * Luc De Meyer <luc.demeyer@noviat.com>
+* Saran Lim. <saranl@ecosoft.co.th>
diff --git a/report_xlsx_helper/report/report_xlsx_abstract.py b/report_xlsx_helper/report/report_xlsx_abstract.py
index 7dadc70f..156e5c39 100644
--- a/report_xlsx_helper/report/report_xlsx_abstract.py
+++ b/report_xlsx_helper/report/report_xlsx_abstract.py
@@ -464,15 +464,16 @@ class ReportXlsxAbstract(models.AbstractModel):
         return row_pos + 2
 
     def _write_line(self, ws, row_pos, ws_params, col_specs_section=None,
-                    render_space=None, default_format=None):
+                    render_space=None, default_format=None,
+                    col_specs='col_specs', wanted_list='wanted_list'):
         """
         Write a line with all columns included in the 'wanted_list'.
         Use the entry defined by the col_specs_section.
         An empty cell will be written if no col_specs_section entry
         for a column.
         """
-        col_specs = ws_params.get('col_specs')
-        wl = ws_params.get('wanted_list') or []
+        col_specs = ws_params.get(col_specs)
+        wl = ws_params.get(wanted_list) or []
         pos = 0
         for col in wl:
             if col not in col_specs: