def __str__(self):
            base = 'HEADER'
            if self.fields:
                base += '.FIELDS'
                if self.negate:
                    base += '.NOT'
                fields = []
                for f in self.fields:
                    f = f.title()
                    if _needsQuote(f):
                        f = _quote(f)
                    fields.append(f)
                base += ' '.join(fields) % ' (%s)'
            if self.part:
                base = '.'.join([str(x + 1) for x in self.part]) + '.' + base
            return base
dataset/ETHPy150Open nlloyd/SubliminalCollaborator/libs/twisted/mail/imap4.py/_FetchParser.Header.__str__/swapped operands of `%`