both are acceptable for `os.access`
`os.R_OK = 4` #(read access)
`os.W_OK = 2` #(write access)
`6` is read/write access.

Follows standard linux permissions handling.

Works as expect, at least for Linux.  However, I'm unable to test on winows, I'll switch to `|` to ensure that it works on windows (not sure what os.R_OK is when running on windows and whether this still relates when summing them).  Cheers @esc24