Format a policy's extant records into a report.

def report(policies, start_date, options, output_fh, raw_output_fh=None):
    """Format a policy's extant records into a report."""
    regions = set([p.options.region for p in policies])
    policy_names = set([p.name for p in policies])
    formatter = Formatter(
        policies[0].resource_manager.resource_type,
        extra_fields=options.field,
        include_default_fields=not options.no_default_fields,
        include_region=len(regions) > 1,
        include_policy=len(policy_names) > 1
    )

    records = []
    for policy in policies:
        # initialize policy execution context for output access
        policy.ctx.initialize()
        if policy.ctx.output.type == 's3':
            policy_records = record_set(
                policy.session_factory,
                policy.ctx.output.config['netloc'],
                policy.ctx.output.config['path'].strip('/'),
                start_date)
        else:
            policy_records = fs_record_set(policy.ctx.log_dir, policy.name)

        log.debug("Found %d records for region %s", len(policy_records), policy.options.region)

        for record in policy_records:
            record['policy'] = policy.name
            record['region'] = policy.options.region

        records += policy_records

    rows = formatter.to_csv(records)

    if options.format == 'csv':
        writer = UnicodeWriter(output_fh, formatter.headers())
        writer.writerow(formatter.headers())
        writer.writerows(rows)
    elif options.format == 'json':
        print(dumps(records, indent=2))
    else:
        # We special case CSV, and for other formats we pass to tabulate
        print(tabulate(rows, formatter.headers(), tablefmt=options.format))

    if raw_output_fh is not None:
        dumps(records, raw_output_fh, indent=2)