Extract metadata from serialized file

def extract_db_info(self, obj, keys):
        """Extract metadata from serialized file"""
        result = {}
        if isinstance(obj, dict):
            try:
                qc = obj['quality_control']
            except KeyError:
                qc = QC.UNKNOWN
        elif isinstance(obj, DataFrame):
            with obj.open() as hdulist:
                qc = self.datamodel.get_quality_control(hdulist)
        else:
            qc = QC.UNKNOWN

        result['quality_control'] = qc
        other = super(DataProductMixin, self).extract_db_info(obj, keys)
        result.update(other)
        return result