code: def _validate_signature_compatibility(self, boxes):
          
          # Check for a bad sequence of boxes.
          # 1st two boxes must be 'jP  ' and 'ftyp'
          if boxes[0].box_id != 'jP  ' or boxes[1].box_id != 'ftyp':
              msg = ("The first box must be the signature box and the second "
                     "must be the file type box.")
              raise IOError(msg)
  
          # The compatibility list must contain at a minimum 'jp2 '.
          if 'jp2 ' not in boxes[1].compatibility_list:
              msg = "The ftyp box must contain 'jp2 ' in the compatibility list."
              raise IOError(msg)
docs: Validate the file signature and compatibility status.