code: def ratio(self, col: str, ratio_col: str="Ratio"):
          
          try:
              df = self.df.copy()
              df[ratio_col] = df[[col]].apply(
                  lambda x: 100 * x / float(x.sum()))
              self.df = df
          except Exception as e:
              self.err(e, self.ratio, "Can not calculate ratio")
docs: Add a column whith the percentages ratio from a column
  
          :param col: column to calculate ratio from
          :type col: str
          :param ratio_col: new ratio column name, defaults to "Ratio"
          :param ratio_col: str, optional
  
          :example: ``ds2 = ds.ratio("Col 1")``