The population of deme S held at 7768 until 712.14 generations back, when it grew reaching 8751, which has been constant since then.
time_units: generations
demes:
  - name: S
    start_time: .inf
    epochs:
      - start_size: 7768
        end_time: 712.14
      - start_size: 8751
        end_time: 0