diff --git a/pycen/ps.py b/pycen/ps.py
index 6f5f442..61921f8 100644
--- a/pycen/ps.py
+++ b/pycen/ps.py
@@ -74,7 +74,7 @@ def ps_r_site_param(id_site=None, nom_site=None, columns=None, last_update=False
     nval = 'param'
     ntyp = 'type'
     df = merge(df,dic, how='left', left_on='id_param', right_on='id', suffixes=(None,'_y'))\
-        .drop(['id_y','id_param'],1) \
+        .drop(columns=['id_y','id_param']) \
         .rename(columns={'description':'desc_param_ps', 'nom':nval})
 
     if raw: