docs: def _cursor_back(self, value):
          """
          Moves the cursor back.
          """
          if value <= 0:
              value = 1
          self._cursor.movePosition(self._cursor.Left, self._cursor.MoveAnchor, value)
          self._text_edit.setTextCursor(self._cursor)
          self._last_cursor_pos = self._cursor.position()