Get all month start date and end date in python

from datetime import datetime, timedelta
import calendar


data = []
selected_start_date = datetime.strptime('2019-01-01', "%Y-%m-%d")
selected_start_date_year = selected_start_date.year
for month in range(1,13):
other_val, num_days = calendar.monthrange(int(selected_start_date_year), int(month))
month_start_date = datetime(int(selected_start_date_year), int(month), 1).strftime("%Y-%m-%d")
month_end_date = datetime(int(selected_start_date_year), int(month), num_days).strftime("%Y-%m-%d")
data.append({'start_date':month_start_date,'end_date':month_end_date})
print "data ______________",data