code: def forward(self, t, y, *, perturb=Perturb.NONE):
      assert isinstance(
          perturb, Perturb
      ), "perturb argument must be of type Perturb enum"
      # This dtype change here might be buggy.
      # The exact time value should be determined inside the solver,
      # but this can slightly change it due to numerical differences during casting.
      if torch.is_complex(t):
          t = t.real
      t = t.to(y.abs().dtype)
      if perturb is Perturb.NEXT:
          # Replace with next smallest representable value.
          t = _nextafter(t, t + 1)
      elif perturb is Perturb.PREV:
          # Replace with prev largest representable value.
          t = _nextafter(t, t - 1)
      else:
          # Do nothing.
          pass
      return self.base_func(t, y)
  
imports: from enum import Enum
  import math
  import numpy
  import torch
  import warnings
  from .event_handling import combine_event_functions
label_desc: Use image node_id 2 for calling the _PerturbFunc obj's underlying member method code with example usage: obj.forward(t, y) and returns: self