input: Write a python function to calculate the number of days between two dates.
  assert days_between_dates(date(2020,1,2), date(2020,2,19)) == 48
  assert days_between_dates(date(2022,5,1), date(2022,5,5)) == 4
  assert days_between_dates(date(2021,12,31), date(2022,1,1)) == 1
output: from datetime import date
  
  def days_between_dates(date1, date2):
      return (date2 - date1).days