docstr: Compute dataset-level mean & std
  
  Returns:
      Tuple of global [mean, std] per channel
docstr_tok: ["Compute","dataset-level","mean","&","std","Returns",":","Tuple","of","global","[","mean",",","std","]","per","channel"]
code: def compute(self) -> Tuple[np.ndarray, np.ndarray]:
      """
      Compute dataset-level mean & std
  
      Returns:
          Tuple of global [mean, std] per channel
      """
      return self.global_mean / self.n_items, np.sqrt(
          self.global_var / self.n_items
      )
  
imports: import numpy
  from typing import Optional, Tuple
label_desc: Use image node_id 4 for calling the DatasetMeanStdCalculator obj's underlying member method code with example usage: obj.compute() and returns: unknown,  np