code: def forward(
      self,
      x: torch.Tensor,
      context: torch.Tensor = None,
      timesteps: int = None,
  ) -> torch.Tensor:
      if self.checkpoint:
          return checkpoint(self._forward, x, context, timesteps)
      else:
          return self._forward(x, context, timesteps=timesteps)
  
file_path: generative-models/sgm/modules/video_attention.py
imports: import torch
  from ..modules.attention import *
  from ..modules.diffusionmodules.util import AlphaBlender, linear, timestep_embedding
label_desc: Use image node_id 2 for calling the VideoTransformerBlock obj's underlying member method code with example usage: obj.forward(x, context, timesteps) and returns: checkpoint, self