Getting Errno 13: Permission Denied as a root user

So basically, I just want to load chess engine which is in the same folder with script

_, engine = await chess.engine.popen_uci('./engine')

What is wrong with this? I am running the script as a root user.

Also, if I load from just 'engine', it says file doesn't exist.

UPT: getting this error

 _, self.engine = await chess.engine.popen_uci(r'' + os.path.join(os.getcwd(), 'engine'))
  File "/usr/local/lib/python3.8/dist-packages/chess/engine.py", line 2642, in popen_uci
    transport, protocol = await UciProtocol.popen(command, setpgrp=setpgrp, **popen_args)
  File "/usr/local/lib/python3.8/dist-packages/chess/engine.py", line 1214, in popen
    return await asyncio.get_running_loop().subprocess_exec(cls, *command, **popen_args)  # type: ignore
  File "/usr/lib/python3.8/asyncio/base_events.py", line 1630, in subprocess_exec
    transport = await self._make_subprocess_transport(
  File "/usr/lib/python3.8/asyncio/unix_events.py", line 197, in _make_subprocess_transport
    transp = _UnixSubprocessTransport(self, protocol, args, shell,
  File "/usr/lib/python3.8/asyncio/base_subprocess.py", line 36, in __init__
    self._start(args=args, shell=shell, stdin=stdin, stdout=stdout,
  File "/usr/lib/python3.8/asyncio/unix_events.py", line 789, in _start
    self._proc = subprocess.Popen(
  File "/usr/lib/python3.8/subprocess.py", line 858, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/lib/python3.8/subprocess.py", line 1704, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
PermissionError: [Errno 13] Permission denied: '/root/ChessBot/engine'```

Resolved this by myself now. Need to execute this on engine file

$ chmod 755 engine

So basically, it changes files permissions to the required ones.