code: def checksum(digits):
      
      remainder = 10
      for digit in digits:
          remainder = (remainder + digit) % 10
          if remainder == 0:
              remainder = 10
          remainder = (remainder * 2) % 11
  
      control_digit = 11 - remainder
      if control_digit == 10:
          control_digit = 0
      return control_digit
docs: Calculate and return control digit for given list of digits based on
      ISO7064, MOD 11,10 standard.