In python, I need a menu that looks like this

Python ISBN Conversion Menu 1. Verify the check digit of an ISBN-10

2. Verify the check digit of an ISBN-13

3. Convert an ISBN-10 to a ISBN-13

4. Convert an ISBN-13 to a ISBN-10

5. Exit

The program itself needs to verify both 10 and 13 digit ISBNs and convert an ISBN 10 to an ISBN-13 and vice versa. here is what I have so far:

def main():

ISBN=int(input('Please enter the 10 digit number: ')) # Ensuring ISBN is an integer

while len(ISBN)!= 10:

print('Please make sure you have entered a number which is exactly 10 characters long.')

ISBN=int(input('Please enter the 10 digit number: '))

continue

def compact(number, convert=False):

## Convert the ISBN to the minimal representation.

number = clean(number, ' -').strip().upper()

if len(number) == 9:

number = '0' + number

if convert:

return to_isbn13(number)

return number

def _calc_isbn10_check_digit(number):

# Calculate the ISBN check digit for 10-digit numbers.

check = sum((i + 1) * int(n)

for i, n in enumerate(number)) % 11

return 'X' if check == 10 else str(check)

def validate(number, convert=False):

# Checks to see if the number provided is a valid ISBN (either a legacy

# 10-digit one or a 13-digit one).

number = compact(number, convert=False)

if not number[:-1].isdigit():

raise InvalidFormat()

if len(number) == 10:

if _calc_isbn10_check_digit(number[:-1]) != number[-1]:

raise InvalidChecksum()

elif len(number) == 13:

ean.validate(number)

else:

raise InvalidLength()

if convert:

number = to_isbn13(number)

## return number

def isbn_type(number):

## Check the passed number and returns 'ISBN13', 'ISBN10' or None (for

## invalid) for checking the type of number passed."""

try:

number = validate(number, convert=False)

except ValidationError:

return None

if len(number) == 10:

return 'ISBN10'

else: # len(number) == 13:

return 'ISBN13'

def is_valid(number):

## Checks to see if the number provided is a valid ISBN (either a legacy

## 10-digit one or a 13-digit one).

try:

return bool(validate(number))

except ValidationError:

return False

def to_isbn13(number):

## Convert the number to ISBN-13 format.

number = number.strip()

min_number = compact(number, convert=False)

if len(min_number) == 13:

return number # nothing to do, already ISBN-13

# put new check digit in place

number = number[:-1] + ean.calc_check_digit('978' + min_number[:-1])

# add prefix

if ' ' in number:

return '978 ' + number

elif '-' in number:

return '978-' + number

else:

return '978' + number

def to_isbn10(number):

## Convert the number to ISBN-10 format.

number = number.strip()

min_number = compact(number, convert=False)

if len(min_number) == 10:

return number # nothing to do, already ISBN-10

elif isbn_type(min_number) != 'ISBN13':

raise InvalidFormat('Not a valid ISBN13.')

elif not number.startswith('978'):

raise InvalidFormat('Does not use 978 Bookland prefix.')

# strip EAN prefix

number = number[3:-1].strip().strip('-')

digit = _calc_isbn10_check_digit(min_number[3:-1])

# append the new check digit

if ' ' in number:

return number + ' ' + digit

elif '-' in number:

return number + '-' + digit

else:

return number + digit

def split(number, convert=False):

## Split the specified ISBN into an EAN.UCC prefix, a group prefix, a

## registrant, an item number and a check-digit.

from stdnum import numdb

# clean up number

number = compact(number, convert)

# get Bookland prefix if any

delprefix = False

if len(number) == 10:

number = '978' + number

delprefix = True

# split the number

result = numdb.get('isbn').split(number[:-1])

itemnr = result.pop() if result else ''

prefix = result.pop(0) if result else ''

group = result.pop(0) if result else ''

publisher = result.pop(0) if result else ''

# return results

return ('' if delprefix else prefix, group, publisher, itemnr, number[-1])

def format(number, separator='-', convert=False):

## Reformat the passed number to the standard format with the EAN.UCC

## prefix (if any), the group prefix, the registrant, the item number and

## the check-digit separated (if possible) by the specified separator.

return separator.join(x for x in split(number, convert) if x)

## Call Main

main()