Parse this person name:

Isabelle Geertsen (1950-1999, flourished 1969-1993)
user
first_name: Isabelle
last_name: Geertsen
middle_names: []
temporal:
- start: 1950
  end: 1999
  type: life_span
- start: 1969
  end: 1993
  type: flourished
titles: []
extra_info: []
assistant