code: def _insert_row(self, i, index):
          
          if i == len(self._index):
              self._add_row(index)
          else:
              self._index.insert(i, index)
              for c in range(len(self._columns)):
                  self._data[c].insert(i, None)
docs: Insert a new row in the DataFrame.
  
          :param i: index location to insert
          :param index: index value to insert into the index list
          :return: nothing