input: Write a python function to calculate the difference in days between two dates.
  assert get_days_diff("2023-10-01", "2023-10-10") == 9
  assert get_days_diff("2023-01-01", "2023-01-01") == 0
  assert get_days_diff("2022-12-31", "2023-01-01") == 1
output: def get_days_diff(date1, date2):
      from datetime import datetime
      
      date_format = "%Y-%m-%d"
      d1 = datetime.strptime(date1, date_format)
      d2 = datetime.strptime(date2, date_format)
      
      return abs((d2 - d1).days)