code: def makeGraph(self):
      # g1 = pg.GraphItem(pos=self.pos, adj=self.links[self.rope], pen=0.2, symbol=None)
      brushes = np.where(
          self.fixed,
          pg.mkBrush(0, 0, 0, 255),
          pg.mkBrush(50, 50, 200, 255),
      )
      g2 = pg.GraphItem(
          pos=self.pos,
          adj=self.links[self.push & self.pull],
          pen=0.5,
          brush=brushes,
          symbol="o",
          size=(self.mass**0.33),
          pxMode=False,
      )
      p = pg.ItemGroup()
      # p.addItem(g1)
      p.addItem(g2)
      return p
  
file_path: pyqtgraph/pyqtgraph/examples/verlet_chain/chain.py
imports: import time
  import numpy
  import pyqtgraph
  from .None import relax
label_desc: Use image node_id 3 for calling the ChainSim obj's underlying member method code with example usage: obj.makeGraph() and returns: p