Parse this person name:

Alf Beckmann, 1784-1857, flourished 1809-1824
user
first_name: Alf
last_name: Beckmann
middle_names: []
temporal:
- start: 1784
  end: 1857
  type: life_span
- start: 1809
  end: 1824
  type: flourished
titles: []
extra_info: []
assistant