docstr: This method is responsible for preparing the GL state options needed to render 
  this item (blending, depth testing, etc). The method is called immediately before painting the item.
code: def setupGLState(self):
      """
      This method is responsible for preparing the GL state options needed to render
      this item (blending, depth testing, etc). The method is called immediately before painting the item.
      """
      for k, v in self.__glOpts.items():
          if v is None:
              continue
          if isinstance(k, str):
              func = getattr(GL, k)
              func(*v)
          else:
              if v is True:
                  glEnable(k)
              else:
                  glDisable(k)
  
imports: from OpenGL.GL import *
  from OpenGL import GL
  from ..None import Transform3D
  from ..Qt import QtCore
label_desc: Use image node_id 26 for calling the GLGraphicsItem obj's underlying member method code with example usage: obj.setupGLState() without return types