[Python] Find out whether filesystem supports extended attributes

I have python program that calls another (external) program:

cmd = [ "unsquashfs", "-n", "-d", dirname, filename ]
subprocess.check_call( cmd )


It worked so far. But now I started running this program in /tmp with tmpfs filesystem, which doesn't support xattrs and program subprocess fails with:

write_xattr: failed to write xattr user.random-seed-creditable for file some/file/somewhere because extended attributes are not supported by the destination filesystem
Ignoring xattrs in filesystem
To avoid this error message, specify -no-xattrs


It very kindly informed me I need to add another param, great. But the program belongs to different team, whole company uses it so I would like to minimize my change and add the param only when needed (when xattrs are not supported) - for all I know somebody somewhere depends on xattrs being set in normal case. So, how do I implement the following?:

if not filesystemSupportsXattrs(dirname):
cmd += ['-no-xattrs']

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