def _set_mime_headers(self, headers):
        for name, value in headers:
            name = name.lower()
            if name == 'project-id-version':
                parts = value.split(' ')
                self.project = u' '.join(parts[:-1])
                self.version = parts[-1]
            elif name == 'report-msgid-bugs-to':
                self.msgid_bugs_address = value
            elif name == 'last-translator':
                self.last_translator = value
            elif name == 'language-team':
                self.language_team = value
            elif name == 'content-type':
                mimetype, params = parse_header(value)
                if 'charset' in params:
                    self.charset = params['charset'].lower()
            elif name == 'plural-forms':
                _, params = parse_header(' ;' + value)
                self._num_plurals = int(params.get('nplurals', 2))
                self._plural_expr = params.get('plural', '(n != 1)')
            elif name == 'pot-creation-date':
                self.creation_date = _parse_datetime_header(value)
            elif name == 'po-revision-date':
                # Keep the value if it's not the default one
                if value not in 'YEAR':
                    self.revision_date = _parse_datetime_header(value)
dataset/ETHPy150Open maraoz/proofofexistence/babel/messages/catalog.py/Catalog._set_mime_headers/swapped operands of `not in`