Python code to find First day of month is business day then week number is previous week number otherwise current [closed]

If following is true, then week_num should be 9.

Week_num M   T   W   T   F   S   S10       29  30  31  1   2   3   4

If 1st of given month is weekend the week_num = week_num.

Thanks in advance.

Ive tried the python business day function and also rotate throw week_num. Couldn't find expected outcomes