import sys 
from PySide2 import QtCore, QtWidgets
from PySide2.QtCore import Qt
import gc

class TableModel(QtCore.QAbstractTableModel):

    def __init__(self, parent=None):
        super().__init__(parent)
        self.foo = "foo"

    def rowCount(self, index): 
        return 1000 if not index.isValid() else 0

    def columnCount(self, index): 
        return 1000 if not index.isValid() else 0

    def data(self, index, role): 
        if index.isValid() and role == Qt.DisplayRole: 
            # return self.foo
            return str((index.row(), index.column()))
        else: 
            return None

    def headerData(self, col, orientation, role):
        return self.foo


    def flags(self, index):
        f = QtCore.Qt.ItemIsEnabled
        return f

    def __del__(self):
        print("Deleted {0}".format(self.__class__))

class TableView(QtWidgets.QTableView):
    def __del__(self):
        print("Deleted {0}".format(self.__class__))

    def closeEvent(self, event):
        self.setParent(None)
        gc.collect()

class MainWidget(QtWidgets.QWidget):
    def __init__(self, parent = None):
        super().__init__(parent)

        self.setLayout(QtWidgets.QHBoxLayout())
        self.pop_tree = QtWidgets.QPushButton("Pop")
        self.pop_tree.clicked.connect(self.onPop)

        self.layout().addWidget(self.pop_tree)

    def onPop(self):
        tableView = TableView(self)
        model = TableModel(tableView)

        tableView.setModel(model)
        tableView.setWindowFlags(QtCore.Qt.Window)
        tableView.show()


def main(): 
    app = QtWidgets.QApplication(sys.argv)

    widget = MainWidget()
    widget.show()

    sys.exit(app.exec_())

if __name__ == '__main__': 
    main()