code: def unregisterCanvas(self, name):
      c = self.canvases[name]
      del self.canvases[name]
      self.sigCanvasListChanged.emit()
  
file_path: pyqtgraph/pyqtgraph/canvas/CanvasManager.py
imports: from ..Qt import QtCore, QtWidgets
  import weakref
label_desc: Use image node_id 4 for calling the CanvasManager obj's underlying member method code with example usage: obj.unregisterCanvas(name) without return types