[Rust]get file name

Mypath.file_name().unwrap().to_string_lossy().into_owned();

Mypath:type of object 
file_name():method of retreaving tail of path and return Option<&OsStr>
unwrap(): method of retreaving Option type
to_string_lossy():method of changing to string(lossy is just like forced)
.into_owned():method of changing to string have Cow