How to use the taskcluster.utils.toStr function in taskcluster

# We need to fix the output of get_bewit.  It returns a url-safe base64
            # encoded string, which contains a list of tokens separated by '\'.
            # The first one is the clientId, the second is an int, the third is
            # url-safe base64 encoded MAC, the fourth is the ext param.
            # The problem is that the nested url-safe base64 encoded MAC must be
            # base64 (i.e. not url safe) or server-side will complain.

            # id + '\\' + exp + '\\' + mac + '\\' + options.ext;
            resource = mohawk.base.Resource(
                credentials={
                    'id': clientId,
                    'key': accessToken,
                    'algorithm': 'sha256',
                },
                method='GET',
                ext=utils.toStr(self.makeHawkExt()),
                url=requestUrl,
                timestamp=expiration,
                nonce='',
                # content='',
                # content_type='',
            )
            bewit = mohawk.bewit.get_bewit(resource)
            return bewit.rstrip('=')

# We need to fix the output of get_bewit.  It returns a url-safe base64
            # encoded string, which contains a list of tokens separated by '\'.
            # The first one is the clientId, the second is an int, the third is
            # url-safe base64 encoded MAC, the fourth is the ext param.
            # The problem is that the nested url-safe base64 encoded MAC must be
            # base64 (i.e. not url safe) or server-side will complain.

            # id + '\\' + exp + '\\' + mac + '\\' + options.ext;
            resource = mohawk.base.Resource(
                credentials={
                    'id': clientId,
                    'key': accessToken,
                    'algorithm': 'sha256',
                },
                method='GET',
                ext=utils.toStr(self.makeHawkExt()),
                url=requestUrl,
                timestamp=expiration,
                nonce='',
                # content='',
                # content_type='',
            )
            bewit = mohawk.bewit.get_bewit(resource)
            return bewit.rstrip('=')

if 'expiration' in kwargs:
            expiration = kwargs['expiration']
            del kwargs['expiration']
        else:
            expiration = self.options['signedUrlExpiration']

        expiration = int(time.time() + expiration)  # Mainly so that we throw if it's not a number

        requestUrl = self.buildUrl(methodName, *args, **kwargs)

        if not self._hasCredentials():
            raise exceptions.TaskclusterAuthFailure('Invalid Hawk Credentials')

        clientId = utils.toStr(self.options['credentials']['clientId'])
        accessToken = utils.toStr(self.options['credentials']['accessToken'])

        def genBewit():
            # We need to fix the output of get_bewit.  It returns a url-safe base64
            # encoded string, which contains a list of tokens separated by '\'.
            # The first one is the clientId, the second is an int, the third is
            # url-safe base64 encoded MAC, the fourth is the ext param.
            # The problem is that the nested url-safe base64 encoded MAC must be
            # base64 (i.e. not url safe) or server-side will complain.

            # id + '\\' + exp + '\\' + mac + '\\' + options.ext;
            resource = mohawk.base.Resource(
                credentials={
                    'id': clientId,
                    'key': accessToken,
                    'algorithm': 'sha256',
                },

if 'expiration' in kwargs:
            expiration = kwargs['expiration']
            del kwargs['expiration']
        else:
            expiration = self.options['signedUrlExpiration']

        expiration = int(time.time() + expiration)  # Mainly so that we throw if it's not a number

        requestUrl = self.buildUrl(methodName, *args, **kwargs)

        if not self._hasCredentials():
            raise exceptions.TaskclusterAuthFailure('Invalid Hawk Credentials')

        clientId = utils.toStr(self.options['credentials']['clientId'])
        accessToken = utils.toStr(self.options['credentials']['accessToken'])

        def genBewit():
            # We need to fix the output of get_bewit.  It returns a url-safe base64
            # encoded string, which contains a list of tokens separated by '\'.
            # The first one is the clientId, the second is an int, the third is
            # url-safe base64 encoded MAC, the fourth is the ext param.
            # The problem is that the nested url-safe base64 encoded MAC must be
            # base64 (i.e. not url safe) or server-side will complain.

            # id + '\\' + exp + '\\' + mac + '\\' + options.ext;
            resource = mohawk.base.Resource(
                credentials={
                    'id': clientId,
                    'key': accessToken,
                    'algorithm': 'sha256',
                },

if expiry - start > datetime.timedelta(days=31):
        raise exceptions.TaskclusterFailure('Only 31 days allowed')

    # We multiply times by 1000 because the auth service is JS and as a result
    # uses milliseconds instead of seconds
    cert = dict(
        version=1,
        scopes=scopes,
        start=calendar.timegm(start.utctimetuple()) * 1000,
        expiry=calendar.timegm(expiry.utctimetuple()) * 1000,
        seed=utils.slugId().encode('ascii') + utils.slugId().encode('ascii'),
    )

    # if this is a named temporary credential, include the issuer in the certificate
    if name:
        cert['issuer'] = utils.toStr(clientId)

    sig = ['version:' + utils.toStr(cert['version'])]
    if name:
        sig.extend([
            'clientId:' + utils.toStr(name),
            'issuer:' + utils.toStr(clientId),
        ])
    sig.extend([
        'seed:' + utils.toStr(cert['seed']),
        'start:' + utils.toStr(cert['start']),
        'expiry:' + utils.toStr(cert['expiry']),
        'scopes:'
    ] + scopes)
    sigStr = '\n'.join(sig).encode()

    if isinstance(accessToken, six.text_type):

cert = dict(
        version=1,
        scopes=scopes,
        start=calendar.timegm(start.utctimetuple()) * 1000,
        expiry=calendar.timegm(expiry.utctimetuple()) * 1000,
        seed=utils.slugId() + utils.slugId(),
    )

    # if this is a named temporary credential, include the issuer in the certificate
    if name:
        cert['issuer'] = utils.toStr(clientId)

    sig = ['version:' + utils.toStr(cert['version'])]
    if name:
        sig.extend([
            'clientId:' + utils.toStr(name),
            'issuer:' + utils.toStr(clientId),
        ])
    sig.extend([
        'seed:' + utils.toStr(cert['seed']),
        'start:' + utils.toStr(cert['start']),
        'expiry:' + utils.toStr(cert['expiry']),
        'scopes:'
    ] + scopes)
    sigStr = '\n'.join(sig).encode()

    if isinstance(accessToken, six.text_type):
        accessToken = accessToken.encode()
    sig = hmac.new(accessToken, sigStr, hashlib.sha256).digest()

    cert['signature'] = utils.encodeStringForB64Header(sig)

# We multiply times by 1000 because the auth service is JS and as a result
    # uses milliseconds instead of seconds
    cert = dict(
        version=1,
        scopes=scopes,
        start=calendar.timegm(start.utctimetuple()) * 1000,
        expiry=calendar.timegm(expiry.utctimetuple()) * 1000,
        seed=utils.slugId() + utils.slugId(),
    )

    # if this is a named temporary credential, include the issuer in the certificate
    if name:
        cert['issuer'] = utils.toStr(clientId)

    sig = ['version:' + utils.toStr(cert['version'])]
    if name:
        sig.extend([
            'clientId:' + utils.toStr(name),
            'issuer:' + utils.toStr(clientId),
        ])
    sig.extend([
        'seed:' + utils.toStr(cert['seed']),
        'start:' + utils.toStr(cert['start']),
        'expiry:' + utils.toStr(cert['expiry']),
        'scopes:'
    ] + scopes)
    sigStr = '\n'.join(sig).encode()

    if isinstance(accessToken, six.text_type):
        accessToken = accessToken.encode()
    sig = hmac.new(accessToken, sigStr, hashlib.sha256).digest()

# We multiply times by 1000 because the auth service is JS and as a result
    # uses milliseconds instead of seconds
    cert = dict(
        version=1,
        scopes=scopes,
        start=calendar.timegm(start.utctimetuple()) * 1000,
        expiry=calendar.timegm(expiry.utctimetuple()) * 1000,
        seed=utils.slugId().encode('ascii') + utils.slugId().encode('ascii'),
    )

    # if this is a named temporary credential, include the issuer in the certificate
    if name:
        cert['issuer'] = utils.toStr(clientId)

    sig = ['version:' + utils.toStr(cert['version'])]
    if name:
        sig.extend([
            'clientId:' + utils.toStr(name),
            'issuer:' + utils.toStr(clientId),
        ])
    sig.extend([
        'seed:' + utils.toStr(cert['seed']),
        'start:' + utils.toStr(cert['start']),
        'expiry:' + utils.toStr(cert['expiry']),
        'scopes:'
    ] + scopes)
    sigStr = '\n'.join(sig).encode()

    if isinstance(accessToken, six.text_type):
        accessToken = accessToken.encode()
    sig = hmac.new(accessToken, sigStr, hashlib.sha256).digest()