Parse this person name:

William Gray (1767-1819, flourished 1785-1804)
user
first_name: William
last_name: Gray
middle_names: []
temporal:
- start: 1767
  end: 1819
  type: life_span
- start: 1785
  end: 1804
  type: flourished
titles: []
extra_info: []
assistant