input: Write a function to retrieve a list of people born after a specified date.
  assert len(get_people_born_after(datetime(2000, 1, 1))) > 0
  assert all(datetime.fromisoformat(person['birth_date']) > datetime(2000, 1, 1) for person in get_people_born_after(datetime(2000, 1, 1)))
  assert len(get_people_born_after(datetime(2025, 1, 1))) == 0
output: def get_people_born_after(date):
      from datetime import datetime
      
      people = [
          {'name': 'Alice', 'birth_date': '2001-05-21'},
          {'name': 'Bob', 'birth_date': '1999-12-15'},
          {'name': 'Charlie', 'birth_date': '2003-07-30'},
          {'name': 'Diana', 'birth_date': '1995-02-20'}
      ]
      
      return [person for person in people if datetime.fromisoformat(person['birth_date']) > date]