Provides struct and type for a FineTuning.Job.Checkpoint
@type t() :: %OpenAi.FineTuning.Job.Checkpoint{ created_at: integer(), fine_tuned_model_checkpoint: String.t(), fine_tuning_job_id: String.t(), id: String.t(), metrics: OpenAi.FineTuning.Job.Checkpoint.Metrics.t(), object: String.t(), step_number: integer() }