code: def check_resize(resize):
      
      if resize is None:
          return
  
      resize = resize.lower().strip()
  
      if 'x' in resize:
          tmp = resize.lower().split('x')
          tmp = [x.strip() for x in resize.split('x')]
          if len(tmp) == 2 and tmp[0].isdigit() and tmp[1].isdigit():
              return
      elif '%' in resize:
          tmp = resize.split('%')[0]
          if tmp.isnumeric():
              tmp = int(tmp)
              if 1 <= tmp <= 1000:
                  return
              else:
                  raise PercentageOutOfRange("percentage must be between 1 and 1000")
  
      raise MallformedResize('Resize value "%s" is mallformed. '
                             'Desired format is: {width}x{height} or {percentage}%%' % resize)
docs: checks resize parameter if illegal value raises exception