@cached_property<EOL><INDENT>def missing_pids(self):<DEDENT>
missing = []<EOL>for p in self.pids:<EOL><INDENT>try:<EOL><INDENT>PersistentIdentifier.get(p.pid_type, p.pid_value)<EOL><DEDENT>except PIDDoesNotExistError:<EOL><INDENT>missing.append(p)<EOL><DEDENT><DEDENT>return missing<EOL>
Filter persistent identifiers.