chronize columns between positive and negative cases.

        Parameters:
        df_ (DataFrame): The DataFrame to process.

        Returns:
        DataFrame: A DataFrame with synchronized columns.
        &#34;&#34;&#34;
        df=df_.copy()
        if self.target_label:
            df1 = df[df[self.target_label] ==  str(self.target_label_positive)]
            df0 = df[df[self.target_label] ==  str(self.target_label_negative)]
            col1 = df1.replace(&#39;&#39;, pd.NA).dropna(axis=1, how=&#39;