Reading Archive from bytes in memory

[rpm5099]

I would like to be able to read archives from memory, however the Archive class doesn't allow that. If you try to pass it using BytesIO it fails because it has a non-functional fileno property (there's no actual file descriptor open). libarchive has a function that seems to support this in archive_read_open_memory(arg1, buff, size) but I cannot seem to convert a python bytes object to the correct type required by that function using ctypes. Everything I've tried ends up with the error:

TypeError: in method 'archive_read_open_memory', argument 2 of type 'void const *'

Could you show the correct way to pass python bytes to that function argument buff? Thanks.