code: def _reverse_index(self):
          
          if self.y == 0:
              # If the cursor is currently at the first row, then scroll the
              # screen up.
              self.display = [u" " * self.size[1]] + self.display[:-1]
          else:
              # If the cursor is anywhere other than the first row than just move
              # it up by one row.
              self.y -= 1
docs: Move the cursor up one row in the same column. If the cursor is at the
          first row, create a new row at the top.