Parse this person name:

Gerrit Koster (1261-1320, flourished 1277-1298)
user
first_name: Gerrit
last_name: Koster
middle_names: []
temporal:
- start: 1261
  end: 1320
  type: life_span
- start: 1277
  end: 1298
  type: flourished
titles: []
extra_info: []
assistant