def get_invalid_ISSNs(self):
return [<EOL>self._clean_isbn(issn)<EOL>for issn in self["<STR_LIT>"] + self["<STR_LIT>"]<EOL>]<EOL>
Get list of invalid ISSNs (``022z`` + ``022y``).

Returns:
    list: List with INVALID ISSN strings.