Overriding method flags

def flags(self, index):
        """Overriding method flags"""
        # This method was implemented in CollectionsModel only, but to enable
        # tuple exploration (even without editing), this method was moved here
        if not index.isValid():
            return Qt.ItemIsEnabled
        return Qt.ItemFlags(QAbstractTableModel.flags(self, index)|
                            Qt.ItemIsEditable)