addDirectory( $directoryName [, $fileName ] )
        Append a member created from the given directory name. The dir
+ectory
        name does not have to name an existing directory. If the named
        directory exists, the file modification time and permissions a
+re set
        from the existing directory, otherwise they are set to now and
        permissive default permissions. $directoryName must be in loca
+l file
        system format. The optional second argument sets the name of t
+he
        archive member (which defaults to $directoryName). If given, i
+t must
        be in Zip (Unix) format. Returns the new member.
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