Get start and end points for: week, month, quarter and year

start_end_day.py

from datetime import date
from dateutil.relativedelta import relativedelta

def start_end_day(sunmon: bool = True):
    today = date.today()
    curr_quarter = int((today.month - 1) / 3 + 1)
    
    dayofweek = [today.weekday(),today.isoweekday()][sunmon]
    
    week_start = today - relativedelta(days=dayofweek)
    week_end = week_start + relativedelta(days=6)
    
    month_start = date(today.year,today.month, 1)
    month_end = month_start + relativedelta(months=1, days=-1)
    
    quarter_start = date(today.year, 3 * curr_quarter - 2, 1)
    quarter_end = quarter_start + relativedelta(months=3, days=-1)
    
    year_start = date(today.year, 1, 1)
    year_end = year_start + relativedelta(years=1, days=-1)
    
    return ((week_start,week_end),(month_start,month_end),(quarter_start,quarter_end),(year_start,year_end))

print(start_end_day(True))