code: def _subtract_column_mean(
      tensor: Tensor, subtract_mean: bool
  ) -> Tensor:
      # subtracts the column mean of the tensor size (m, n) if subtract_mean=True
      # it returns size (m, n)
      if subtract_mean:
          col_means = torch.mean(tensor, dim=0).unsqueeze(0)
          tensor = tensor - col_means
      return tensor
  
imports: import math
  from typing import Tuple
  import torch
  import torchaudio
  from torch import Tensor
label_desc: Use image node_id 8 for calling a global function with example usage: _subtract_column_mean(tensor, subtract_mean) and returns: tensor