For deme W, the population count was 1930 until a change 9444.1921 generations ago, where it changed to 4798, remaining steady thereafter.
time_units: generations
demes:
  - name: W
    start_time: .inf
    epochs:
      - start_size: 1930
        end_time: 9444.1921
      - start_size: 4798
        end_time: 0