code: def closeEvent(self, ev):
      MatplotlibExporter.windows.remove(self)
      self.deleteLater()
  
file_path: pyqtgraph/pyqtgraph/exporters/Matplotlib.py
imports: from ..None import PlotItem
  from ..None import functions
  from ..Qt import QtCore, QtWidgets
  from .Exporter import Exporter
label_desc: Use image node_id 3 for calling the MatplotlibWindow obj's underlying member method code with example usage: obj.closeEvent(ev) without return types