<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def process_line(self, record):
        "Process a single record. This assumes only a single sample output."
        cleaned = []

        for key in self.vcf_fields:
            out = self.process_column(key, getattr(record, key))
            if isinstance(out, (list, tuple)):
                cleaned.extend(out)
            else:
                cleaned.append(out)

        for key in self.info_fields:
            out = self.process_column(key, record.INFO.get(key, None))
            if isinstance(out, (list, tuple)):
                cleaned.extend(out)
            else:
                cleaned.append(out)

        return cleaned