Parse this person name:

Bertram Lehmann, 1209-1257, flourished 1235-1246
user
first_name: Bertram
last_name: Lehmann
middle_names: []
temporal:
- start: 1209
  end: 1257
  type: life_span
- start: 1235
  end: 1246
  type: flourished
titles: []
extra_info: []
assistant