Parse this person name:

Stef Koster (1379-1435, flourished 1398-1409)
user
first_name: Stef
last_name: Koster
middle_names: []
temporal:
- start: 1379
  end: 1435
  type: life_span
- start: 1398
  end: 1409
  type: flourished
titles: []
extra_info: []
assistant