code: def sample_time(self, batch_size, device=None):
      return self.scheduler.sample_random_times(
          batch_size=batch_size, device=device
      )
  
imports: import torch
  import torch.nn.functional
  from nemo.collections.multimodal.modules.imagen.sampler.batch_ops import batch_mul
  from nemo.collections.multimodal.modules.imagen.sampler.continuous_ddpm import GaussianDiffusionContinuousTimes
  from nemo.collections.multimodal.parts.utils import randn_like
label_desc: Use image node_id 2 for calling the ContinousDDPMPrecond obj's underlying member method code with example usage: obj.sample_time(batch_size, device) and returns: self