Problem: BytesIO class does not have an isatty() method. CPython implements it by checking if closed and returning False.

RustPython Location: crates/vm/src/stdlib/io.rs:4530-4750 - no isatty() pymethod found

CPython 3.14 Reference: Modules/_io/bytesio.c:401-406

static PyObject *
_io_BytesIO_isatty_impl(bytesio *self)
/*[clinic end generated code: output=8ca595fbfb51f24f input=b0b63260f6e4cd5e]*/
{
    CHECK_CLOSED(self);
    Py_RETURN_FALSE;
}