Issue #12715: Add an optional symlinks argument to shutil functions (copyfile, copymode, copystat, copy, copy2).
When that parameter is true, symlinks aren't dereferenced and the operation
instead acts on the symlink itself (or creates one, if relevant).

Patch by Hynek Schlawack.

use list() to wrap range() in itertools.permutations() example; thanks to Romain MORLEVAT from docs@

dropped connections in case of simultaneous connection requests.

dropped connections in case of simultaneous connection requests.