Parse this person name:

Sergej Flantz (1754-1825, flourished 1771-1781)
user
first_name: Sergej
last_name: Flantz
middle_names: []
temporal:
- start: 1754
  end: 1825
  type: life_span
- start: 1771
  end: 1781
  type: flourished
titles: []
extra_info: []
assistant