The population of deme V held at 3751 until 3768.6 generations back, when it changed reaching 8001, which has been constant since then.
time_units: generations
demes:
  - name: V
    start_time: .inf
    epochs:
      - start_size: 3751
        end_time: 3768.6
      - start_size: 8001
        end_time: 0