"bytes==1-10",
		"bytes=",
		"bytes=aa",
		"aa",
		"",
		"bytes=1-10-",
		"bytes=1--10",
		"bytes=-1-10",
		"bytes=0-+3",
		"bytes=+3-+5",
		"bytes=10-11,12-10", // Unsupported by S3/MinIO (valid in RFC)
	}
	for i, urs := range unparsableRangeSpecs {
		rs, err := parseRequestRangeSpec(urs)
		if err == nil {
			t.Errorf("Case %d: Did not get an expected error - got %v", i, rs)
		}
		if isErrInvalidRange(err) {

******@****.***
******@****.***
arcfour256
arcfour128
arcfour
aes128-cbc
3des-cbc
```

`--sftp=mac-algos=...` specifies a default set of MAC algorithms in preference order.
This is based on RFC 4253, section 6.4, but with hmac-md5 variants removed because they have 
reached the end of their useful life.

Valid values: 

```
******@****.***
******@****.***
hmac-sha2-256