docstr: Get min/max values for each band in the image
docstr_tok: ["Get","min\/max","values","for","each","band","in","the","image"]
code: def _getextrema(self):
      """Get min/max values for each band in the image"""
  
      def minmax(histogram):
          res_min, res_max = 255, 0
          for i in range(256):
              if histogram[i]:
                  res_min = i
                  break
          for i in range(255, -1, -1):
              if histogram[i]:
                  res_max = i
                  break
          return res_min, res_max
  
      return [minmax(self.h[i:]) for i in range(0, len(self.h), 256)]
  
file_path: pillow/src/PIL/ImageStat.py
imports: from __future__ import annotations
  import math
label_desc: Use image node_id 3 for calling the Stat obj's underlying member method code with example usage: obj._getextrema() and returns: unknown, res_min,  res_max