def delete(self, doc):
        if doc.id is None:
            raise DatabaseException('Document does not have id')
        if doc.sid is None:
            try:
                rs = self.db.docs.remove({'id': doc.id}, safe=True)
                assert rs['n'] == 1
            except Exception as e:
                raise DatabaseException(e)
            return None
        doc.data = None
        return self.update(doc)
def display(self, callingWindow, srcContext, mainItem):
        if srcContext not in ("marketItemGroup", "marketItemMisc") or self.mainFrame.getActiveFit() is None:
            return False

        if mainItem is None:
            return False

        for attr in ("emDamage", "thermalDamage", "explosiveDamage", "kineticDamage"):
            if mainItem.getAttribute(attr) is not None:
                return True

        return False