code: def instance(cls):
      return CanvasManager.SINGLETON
  
file_path: pyqtgraph/pyqtgraph/canvas/CanvasManager.py
imports: from ..Qt import QtCore, QtWidgets
  import weakref
label_desc: Use image node_id 2 for calling the CanvasManager obj's underlying member method code with example usage: obj.instance(cls) and returns: CanvasManager