removing a certain number from the output

I need help with this code

chapter_count_book_a = 3
verse_count_book_a = [2,2,2]


def get_book_data(book,chapter_count, verse_count):
    if chapter_count != len(verse_count):
       print("ERROR!!!")
    answer = []
    for chapter in range(0,chapter_count):
        chp = book + "." + str(chapter+1)
        next_verse = verse_count[chapter]
        for verse in range(0,next_verse):
            answer.append(chp+"."+str(verse+1))
    return answer
book_a_data = get_book_data("",chapter_count_book_a, verse_count_book_a)

print(book_a_data)

I have this code here, I try to remove it from every verse and chapter -7

I’m looking for this output if I have ['.1.1', '.1.2', '.2.1', '.2.2', '.3.1', '.3.2']

I want ['.-6.-6', '.-6.-5', '.-5.-6', '.-4.-4', '.-4.-6', '.-4.-5']
the number 10.10 should have an output of 3.3

How do I do that? I’m new to Python, so I’m going to need help from someone more advanced thanx

>Solution :

Maybe it’s not the more pythonic way but it works:

result=[]
for chapter in book_a_data:
    for number in chapter.split("."):
        if number.isdigit():
            chapter = chapter.replace(number, f"{int(number)-7}", 1)
    result.append(chapter)

print(result)

Result:

['.1.1', '.1.2', '.2.1', '.2.2', '.3.1', '.3.2']
['.-6.-6', '.-6.-5', '.-5.-6', '.-5.-5', '.-4.-6', '.-4.-5']