Deme D maintained a population of 4023 until there was a shift 499.467 generations ago that changed its numbers to 2082, a figure that has remained the same since.
time_units: generations
demes:
  - name: D
    start_time: .inf
    epochs:
      - start_size: 4023
        end_time: 499.467
      - start_size: 2082
        end_time: 0