Parse this person name:

Ian Keijser, 1202-1250, flourished 1217-1228
user
first_name: Ian
last_name: Keijser
middle_names: []
temporal:
- start: 1202
  end: 1250
  type: life_span
- start: 1217
  end: 1228
  type: flourished
titles: []
extra_info: []
assistant