Deme B maintained a population of 6369 until there was a shift 4522.36 generations ago that changed its numbers to 7927, a figure that has remained the same since.
time_units: generations
demes:
  - name: B
    start_time: .inf
    epochs:
      - start_size: 6369
        end_time: 4522.36
      - start_size: 7927
        end_time: 0