code: def add_blank_row(self, label):
          
          col_labels = self.df.columns
          blank_item = pd.Series({}, index=col_labels, name=label)
          # use .loc to add in place (append won't do that)
          self.df.loc[blank_item.name] = blank_item
          return self.df
docs: Add a blank row with only an index value to self.df.
          This is done inplace.