How to use the taskcluster.exceptions function in taskcluster

},
                method='GET',
                ext=utils.toStr(self.makeHawkExt()),
                url=requestUrl,
                timestamp=expiration,
                nonce='',
                # content='',
                # content_type='',
            )
            bewit = mohawk.bewit.get_bewit(resource)
            return bewit.rstrip('=')

        bewit = genBewit()

        if not bewit:
            raise exceptions.TaskclusterFailure('Did not receive a bewit')

        u = urllib.parse.urlparse(requestUrl)

        qs = u.query
        if qs:
            qs += '&'
        qs += 'bewit=%s' % bewit

        return urllib.parse.urlunparse((
            u.scheme,
            u.netloc,
            u.path,
            u.params,
            qs,
            u.fragment,
        ))

raise exceptions.TaskclusterFailure('Specify either positional or key word arguments')

        # We know for sure that if we don't give enough arguments that the call
        # should fail.  We don't yet know if we should fail because of two many
        # arguments because we might be overwriting positional ones with kw ones
        if len(reqArgs) > len(args) + len(kwApiArgs):
            raise exceptions.TaskclusterFailure(
                '%s takes %d args, only %d were given' % (
                    entry['name'], len(reqArgs), len(args) + len(kwApiArgs)))

        # We also need to error out when we have more positional args than required
        # because we'll need to go through the lists of provided and required args
        # at the same time.  Not disqualifying early means we'll get IndexErrors if
        # there are more positional arguments than required
        if len(args) > len(reqArgs):
            raise exceptions.TaskclusterFailure('%s called with too many positional args',
                                                entry['name'])

        i = 0
        for arg in args:
            log.debug('Found a positional argument: %s', arg)
            routeParams[reqArgs[i]] = arg
            i += 1

        log.debug('After processing positional arguments, we have: %s', routeParams)

        routeParams.update(kwApiArgs)

        log.debug('After keyword arguments, we have: %s', routeParams)

        if len(reqArgs) != len(routeParams):
            errMsg = '%s takes %s args, %s given' % (

def fetch_secret_from_taskcluster(name):
    try:
        secrets = taskcluster.Secrets({
            # BaseUrl is still needed for tasks that haven't migrated to taskgraph yet.
            'baseUrl': 'http://taskcluster/secrets/v1',
        })
    except taskcluster.exceptions.TaskclusterFailure:
        # taskcluster library >=5 errors out when `baseUrl` is used
        secrets = taskcluster.Secrets({
            'rootUrl': os.environ.get('TASKCLUSTER_PROXY_URL', 'https://taskcluster.net'),
        })

    return secrets.get(name)

log.debug('Not using hawk!')
                headers = {}
            if payload:
                # Set header for JSON if payload is given, note that we serialize
                # outside this loop.
                headers['Content-Type'] = 'application/json'

            log.debug('Making attempt %d', retry)
            try:
                response = utils.makeSingleHttpRequest(method, url, payload, headers)
            except requests.exceptions.RequestException as rerr:
                if retry < retries:
                    log.warn('Retrying because of: %s' % rerr)
                    continue
                # raise a connection exception
                raise exceptions.TaskclusterConnectionError(
                    "Failed to establish connection",
                    superExc=rerr
                )

            # Handle non 2xx status code and retry if possible
            status = response.status_code
            if status == 204:
                return None

            # Catch retryable errors and go to the beginning of the loop
            # to do the retry
            if 500 <= status and status < 600 and retry < retries:
                log.warn('Retrying because of a %s status code' % status)
                continue

            # Throw errors for non-retryable errors

log.debug('Not using hawk!')
                headers = {}
            if payload:
                # Set header for JSON if payload is given, note that we serialize
                # outside this loop.
                headers['Content-Type'] = 'application/json'

            log.debug('Making attempt %d', retry)
            try:
                response = utils.makeSingleHttpRequest(method, url, payload, headers)
            except requests.exceptions.RequestException as rerr:
                if retry < retries:
                    log.warn('Retrying because of: %s' % rerr)
                    continue
                # raise a connection exception
                raise exceptions.TaskclusterConnectionError(
                    "Failed to establish connection",
                    superExc=rerr
                )

            # Handle non 2xx status code and retry if possible
            status = response.status_code
            if status == 204:
                return None

            # Catch retryable errors and go to the beginning of the loop
            # to do the retry
            if 500 <= status and status < 600 and retry < retries:
                log.warn('Retrying because of a %s status code' % status)
                continue

            # Throw errors for non-retryable errors

raise exceptions.TaskclusterFailure(
                    'Positional arg "%s" to %s is not a string or int' % (arg, entry['name']))

        for name, arg in six.iteritems(kwApiArgs):
            if not isinstance(arg, six.string_types) and not isinstance(arg, int):
                raise exceptions.TaskclusterFailure(
                    'KW arg "%s: %s" to %s is not a string or int' % (name, arg, entry['name']))

        if len(args) > 0 and len(kwApiArgs) > 0:
            raise exceptions.TaskclusterFailure('Specify either positional or key word arguments')

        # We know for sure that if we don't give enough arguments that the call
        # should fail.  We don't yet know if we should fail because of two many
        # arguments because we might be overwriting positional ones with kw ones
        if len(reqArgs) > len(args) + len(kwApiArgs):
            raise exceptions.TaskclusterFailure(
                '%s takes %d args, only %d were given' % (
                    entry['name'], len(reqArgs), len(args) + len(kwApiArgs)))

        # We also need to error out when we have more positional args than required
        # because we'll need to go through the lists of provided and required args
        # at the same time.  Not disqualifying early means we'll get IndexErrors if
        # there are more positional arguments than required
        if len(args) > len(reqArgs):
            raise exceptions.TaskclusterFailure('%s called with too many positional args',
                                                entry['name'])

        i = 0
        for arg in args:
            log.debug('Found a positional argument: %s', arg)
            routeParams[reqArgs[i]] = arg
            i += 1

def __init__(self, options=None, session=None):
        if options and options.get('baseUrl'):
            raise exceptions.TaskclusterFailure('baseUrl option is no longer allowed')
        o = copy.deepcopy(self.classOptions)
        o.update(_defaultConfig)
        if options:
            o.update(options)
        if not o.get('rootUrl'):
            raise exceptions.TaskclusterFailure('rootUrl option is required')

        credentials = o.get('credentials')
        if credentials:
            for x in ('accessToken', 'clientId', 'certificate'):
                value = credentials.get(x)
                if value and not isinstance(value, six.binary_type):
                    try:
                        credentials[x] = credentials[x].encode('ascii')
                    except Exception:
                        s = '%s (%s) must be unicode encodable' % (x, credentials[x])