Parse this person name:

Gregory Walker (1938-2009, flourished 1961-1972)
user
first_name: Gregory
last_name: Walker
middle_names: []
temporal:
- start: 1938
  end: 2009
  type: life_span
- start: 1961
  end: 1972
  type: flourished
titles: []
extra_info: []
assistant