The population of deme F held at 2178 until 7271.44 generations back, when it grew reaching 4366, which has been constant since then.
time_units: generations
demes:
  - name: F
    start_time: .inf
    epochs:
      - start_size: 2178
        end_time: 7271.44
      - start_size: 4366
        end_time: 0