Set the upstream operations for operation run.

def set_op_upstreams(op_run, op):
    """Set the upstream operations for operation run."""
    # We get a list of all upstream ops or the current op
    upstream_ops = op.upstream_operations.values_list('id', flat=True)
    # We get latest op runs for the upstream_ops
    latest_op_runs = OperationRun.objects.filter(id__in=upstream_ops)
    latest_op_runs = latest_op_runs.annotate(max_date=Max('created_at'))
    latest_op_runs = latest_op_runs.filter(date=F('max_date'))
    # Set the upstream ops
    op_run.set(latest_op_runs)