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 paint(self):
      if (
          self.scatter.pos is None
          or self.edges is None
          or self.edgeColor is None
      ):
          return None
      verts = self.scatter.pos
      edges = self.edges.astype(np.uint32).flatten()
      glEnableClientState(GL_VERTEX_ARRAY)
      try:
          glColor4f(*self.edgeColor.getRgbF())
          glLineWidth(self.edgeWidth)
          glVertexPointerf(verts)
          glDrawElements(
              GL_LINES, edges.shape[0], GL_UNSIGNED_INT, edges
          )
      finally:
          glDisableClientState(GL_VERTEX_ARRAY)
      return None
  
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 4 for calling the GLGraphItem obj's underlying member method code with example usage: obj.paint() and returns: None, None