f its
    parent (if it has one); a file path can not have two children with the same
    name.  This name is referred to as the file path's "base name".

    A series of such names can be used to locate nested children of a file
    path; such a series is referred to as the child's "path", relative to the
    parent.  In this case, each name in the path is referred to as a "path
    segment"; the child's base name is the segment in the path.

    When representing a file path as a string, a "path separator" is used to
    delimit the path segments within the string.  For a file system path, that
    would be C{os.sep}.

    Note that the values of child names may be restricted.  For example, a file
    system path will not allow the use of the path separator in a name, and
    certain names (e.g. C{"."} and C{".."}) may be reserved or have special
    meanings.

    @since: 12.1
    z3The path separator to use in string representationsc