class_docstr: A GLGraphItem displays graph information as
  a set of nodes connected by lines (as in 'graph theory', not 'graphics').
  Useful for drawing networks, trees, etc.
code: def initializeGL(self):
      self.scatter.initializeGL()
  
file_path: pyqtgraph/pyqtgraph/opengl/items/GLGraphItem.py
imports: from OpenGL.GL import *
  import numpy
  from ...None import functions
  from ...Qt import QtCore, QtGui
  from ..GLGraphicsItem import GLGraphicsItem
  from .GLScatterPlotItem import GLScatterPlotItem
label_desc: Use image node_id 3 for calling the GLGraphItem obj's underlying member method code with example usage: obj.initializeGL() without return types