code: def allowDeletion(store, tableClass, comparisonFactory):
      
      for cascadingAttr in (_disallows.get(tableClass, []) +
                            _disallows.get(None, [])):
          for cascadedItem in store.query(cascadingAttr.type,
                                          comparisonFactory(cascadingAttr),
                                          limit=1):
              return False
  
      return True
docs: Returns a C{bool} indicating whether deletion of an item or items of a
      particular item type should be allowed to proceed.
  
      @param tableClass: An L{Item} subclass.
  
      @param comparison: A one-argument callable taking an attribute and
      returning an L{iaxiom.IComparison} describing the items to
      collect.
  
      @return: A C{bool} indicating whether deletion should be allowed.