This code makes you enter a date range, it will divide that range into 12 sections, checking if a target is in those 12 sections and what the index of that section is.

section-dates.ipynb

#%%
from datetime import *
from dateutil.relativedelta import *
from dateutil.rrule import *

start_date = '01/01/2019'
end_date = '31/12/2019' # Not necessary
target = '01/07/2019'
chunk_size = 12

def chunk_it(list_input: list):
    avg = len(list_input) / float(12)
    list_out = []
    last = 0.0
    while last < len(list_input):
        list_out.append(list_input[int(last):int(last + avg)])
        last += avg
    return list_out

def get_section(start, target):
    start_date = datetime.strptime(start, '%d/%m/%Y')
    target_date = datetime.strptime(target, '%d/%m/%Y')
    end_date = start_date + relativedelta(days=+365)
    
    all_dates = list(rrule(DAILY, dtstart=start_date, until=end_date))
    if target_date not in all_dates:
        return -1
    
    all_dates = chunk_it(all_dates)
      
    for part in all_dates:
        if target_date in part:
            return all_dates.index(part)

print(get_section(start_date, target))
#%%