# Explanation

*Keep transactions before and until a past date* will filter the transactions history on a period having as boundaries : 
- A fixed past date **T** as the newest date.
- A date before the fixed past date as the oldest date, defined as "**T** - (**time_frame** x **time_unit**)", where:
  - ***time_unit***: is the time unit to substract from **T**. It can be:
      - Hours.
      - Days.
      - Weeks.
      - Months.
      - Years.
    
  - ***time_frame***: is the quantity of ***time_unit*** to substract from **T**.


![dates_filtering_strategy_keep_before_and_until_a_past_date.png](9RH6Zs13FwCC)