fork.py

import osfrom upstream import Upstream client = Upstream(api_key=os.environ["UPSTREAM_API_KEY"]) with client.sandbox(template="python") as base:    base.write_file("/workspace/state.txt", "prepared")     child = base.fork()    child.write_file("/workspace/state.txt", "changed in the fork")     print(base.read_file_text("/workspace/state.txt"))    # prepared    print(child.read_file_text("/workspace/state.txt"))   # changed in the fork    child.destroy()