Parse this person name:

William Gross (1808-1877, flourished 1838-1857)
user
first_name: William
last_name: Gross
middle_names: []
temporal:
- start: 1808
  end: 1877
  type: life_span
- start: 1838
  end: 1857
  type: flourished
titles: []
extra_info: []
assistant