diff --git a/eds_scikit/utils/sort_first_koalas.py b/eds_scikit/utils/sort_first_koalas.py
index 52508f45..c5687d6f 100644
--- a/eds_scikit/utils/sort_first_koalas.py
+++ b/eds_scikit/utils/sort_first_koalas.py
@@ -4,17 +4,18 @@
 
 
 def sort_values_first_koalas(
-    dataframe: DataFrame, by_cols: List[str], cols: List[str], ascending: bool = True
+    dataframe: DataFrame, by_cols: List[str], cols: List[str], disambiguate_col: str, ascending: bool = True
 ) -> DataFrame:
-    """Use this function to obtain in koalas the same ouput as dataframe.sort_values(cols).groupby(by_cols).first() in pandas.
+    """Use this function to obtain in koalas the same ouput as dataframe.sort_values([*cols, disambiguate_col]).groupby(by_cols).first() in pandas.
 
-    If you want the output to be deterministic, provide an id column of your dataframe as the last element of variable cols.
+    disambiguate_col must be provided to make sure the output is deterministic 
 
     Parameters
     ----------
     dataframe : DataFrame
     by_cols : List[str]
     cols : List[str]
+    disambiguate_col : List[str]
     ascending : bool, optional
 
     Returns
@@ -22,6 +23,7 @@ def sort_values_first_koalas(
     DataFrame
 
     """
+    cols = [*cols, disambiguate_col]
     for col in cols:
         dataframe_min_max = dataframe.groupby(by_cols, as_index=False)[col]
         dataframe_min_max = (