code: def _deleteComboBoxes(self, row):
          
          tree = self.tree
          model = self.tree.model()
  
          for col in range(self.COL_FIRST_COMBO, self.maxCombos):
              logger.debug("Removing combobox at: ({}, {})".format(row, col))
              tree.setIndexWidget(model.index(row, col), None)
  
          self._comboBoxes = []
docs: Deletes all comboboxes of a row