code: def forward(self, t, state):
      pos, vel, *rest = state
      dpos = vel
      dvel = torch.tanh(self.dvel(torch.zeros_like(vel))) * self.scale
      return (dpos, dvel, *[torch.zeros_like(r) for r in rest])
  
imports: import argparse
  import os
  import math
  import matplotlib.pyplot
  import torch
  import torch.nn
  from torchdiffeq import odeint, odeint_event
  from bouncing_ball import BouncingBallExample
label_desc: Use image node_id 2 for calling the HamiltonianDynamics obj's underlying member method code with example usage: obj.forward(t, state) and returns: dpos,  dvel,  unknown