Deme N maintained a population of 1338 until there was a shift 2183.0 generations ago that grew its numbers to 3859, a figure that has remained the same since.
time_units: generations
demes:
  - name: N
    start_time: .inf
    epochs:
      - start_size: 1338
        end_time: 2183.0
      - start_size: 3859
        end_time: 0