@staticmethod
def _get_workers_with_max_size(worker_to_size):
    """Get workers with maximal size"""
    max_workers = set()
    max_size = 0
    for w, size in worker_to_size.items():
        if size > max_size:
            max_size = size
            max_workers = {w}
        elif size == max_size:
            max_workers.add(w)
    max_workers.difference_update([None])
    return max_size, list(max_workers)
