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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def run_account(account, region, policies_config, output_path, cache_period, cache_path, metrics, dryrun, debug):
 """Execute a set of policies on an account. """

    logging.getLogger('custodian.output').setLevel(logging.ERROR + 1)
    CONN_CACHE.session = None
    CONN_CACHE.time = None

    # allow users to specify interpolated output paths
    if '{' not in output_path:
        output_path = os.path.join(output_path, account['name'], region)

    cache_path = os.path.join(cache_path, "%s-%s.cache" % (account['account_id'], region))

    config = Config.empty(
        region=region, cache=cache_path,
        cache_period=cache_period, dryrun=dryrun, output_dir=output_path,
        account_id=account['account_id'], metrics_enabled=metrics,
        log_group=None, profile=None, external_id=None)

    env_vars = account_tags(account)

    if account.get('role'):
        if isinstance(account['role'], six.string_types):
            config['assume_role'] = account['role']
            config['external_id'] = account.get('external_id')
        else:
            env_vars.update(
                _get_env_creds(get_session(account, 'custodian', region), region))

    elif account.get('profile'):
        config['profile'] = account['profile']

    policies = PolicyCollection.from_data(policies_config, config)
    policy_counts = {}
    success = True
    st = time.time()

    with environ(**env_vars):
        for p in policies:
            # Variable expansion and non schema validation (not optional)
            p.expand_variables(p.get_variables(account.get('vars', {})))
            p.validate()

            log.debug(
                "Running policy:%s account:%s region:%s",
                p.name, account['name'], region)
            try:
                resources = p.run()
                policy_counts[p.name] = resources and len(resources) or 0
                if not resources:
                    continue
                log.info(
                    "Ran account:%s region:%s policy:%s matched:%d time:%0.2f",
                    account['name'], region, p.name, len(resources),
                    time.time() - st)
            except ClientError as e:
                success = False
                if e.response['Error']['Code'] == 'AccessDenied':
                    log.warning('Access denied account:%s region:%s',
                                account['name'], region)
                    return policy_counts, success
                log.error(
                    "Exception running policy:%s account:%s region:%s error:%s",
                    p.name, account['name'], region, e)
                continue
            except Exception as e:
                success = False
                log.error(
                    "Exception running policy:%s account:%s region:%s error:%s",
                    p.name, account['name'], region, e)
                if not debug:
                    continue
                import traceback, pdb, sys
                traceback.print_exc()
                pdb.post_mortem(sys.exc_info()[-1])
                raise

    return policy_counts, success