<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def show_stacking(self):
 """Visualizes pi-stacking interactions."""

        grp = self.getPseudoBondGroup("pi-Stacking-%i" % self.tid, associateWith=[self.model])
        grp.lineWidth = 3
        grp.lineType = self.chimera.Dash
        for i, stack in enumerate(self.plcomplex.pistacking):

            m = self.model
            r = m.newResidue("pseudoatoms", " ", 1, " ")
            centroid_prot = m.newAtom("CENTROID", self.chimera.Element("CENTROID"))
            x, y, z = stack.proteinring_center
            centroid_prot.setCoord(self.chimera.Coord(x, y, z))
            r.addAtom(centroid_prot)

            centroid_lig = m.newAtom("CENTROID", self.chimera.Element("CENTROID"))
            x, y, z = stack.ligandring_center
            centroid_lig.setCoord(self.chimera.Coord(x, y, z))
            r.addAtom(centroid_lig)

            b = grp.newPseudoBond(centroid_lig, centroid_prot)
            b.color = self.colorbyname('forest green')

            self.bs_res_ids += stack.proteinring_atoms