code: def l2_loss(x, y):
      return 2 - 2 * (x * y).sum(dim=-1)
  
imports: import math
  import numpy
  import torch
  import torch.nn
  import torch.nn.functional
  import slowfast.models.losses
  import slowfast.utils.distributed
  import slowfast.utils.logging
  from slowfast.models.video_model_builder import X3D, MViT, ResNet, SlowFast
  from .build import MODEL_REGISTRY
label_desc: Use image node_id 1 for calling a global function with example usage: l2_loss(x, y) and returns: unknown