Parse this person name:

Sierra Johnson, 1270-1321, flourished 1286-1301
user
first_name: Sierra
last_name: Johnson
middle_names: []
temporal:
- start: 1270
  end: 1321
  type: life_span
- start: 1286
  end: 1301
  type: flourished
titles: []
extra_info: []
assistant