code: def delete_all_rows(self):
          
          del self._index[:]
          for c in range(len(self._columns)):
              del self._data[c][:]
docs: Deletes the contents of all rows in the DataFrame. This function is faster than delete_rows() to remove all
          information, and at the same time it keeps the container lists for the columns and index so if there is another
          object that references this DataFrame, like a ViewSeries, the reference remains in tact.
          
          :return: nothing