code: def mean_flat(tensor):
      r"""
      Take the mean over all non-batch dimensions.
      """
      return tensor.mean(dim=list(range(1, len(tensor.shape))))
  
imports: import enum
  import math
  import copy
  import numpy
  import torch
  import torch.nn.functional
  import torch.nn
  from recbole.model.init import xavier_normal_initialization
  from recbole.utils.enum_type import InputType
  from recbole.model.abstract_recommender import AutoEncoderMixin, GeneralRecommender
  from recbole.model.layers import MLPLayers
  import typing
label_desc: Use image node_id 4 for calling a global function with example usage: mean_flat(tensor) and returns: tensor