The population of deme Q held at 4127 until 2304.8 generations back, when it changed reaching 9657, which has been constant since then.
time_units: generations
demes:
  - name: Q
    start_time: .inf
    epochs:
      - start_size: 4127
        end_time: 2304.8
      - start_size: 9657
        end_time: 0