code: def deleteSelected(self):
          'Delete all selected rows.'
          ndeleted = self.deleteBy(self.isSelected)
          nselected = len(self._selectedRows)
          self._selectedRows.clear()
          if ndeleted != nselected:
              error('expected %s' % nselectedf deleteSelected(self):
          'Delete all selected rows.'
          ndeleted = self.deleteBy(self.isSelected)
          nselected = len(self._selectedRows)
          self._selectedRows.clear()
          if ndeleted != nselected:
              error('expected %s' % nselected)
docs: Delete all selected rows.