diff --git a/osc_sdk_python/__init__.py b/osc_sdk_python/__init__.py
index 6a0700b..98c3ad4 100644
--- a/osc_sdk_python/__init__.py
+++ b/osc_sdk_python/__init__.py
@@ -5,6 +5,7 @@
 from .outscale_gateway import LOG_MEMORY
 from .version import get_version
 from .problem import Problem, ProblemDecoder
+from .limiter import RateLimiter
 
 # what to Log
 from .outscale_gateway import LOG_ALL
@@ -23,5 +24,6 @@
     "LOG_ALL",
     "LOG_KEEP_ONLY_LAST_REQ",
     "Problem",
-    "ProblemDecoder"
+    "ProblemDecoder",
+    "RateLimiter",
 ]
diff --git a/osc_sdk_python/authentication.py b/osc_sdk_python/authentication.py
index b319e86..23fd8ac 100644
--- a/osc_sdk_python/authentication.py
+++ b/osc_sdk_python/authentication.py
@@ -5,16 +5,23 @@
 
 from .version import get_version
 from .credentials import Profile
+
 VERSION: str = get_version()
 DEFAULT_USER_AGENT = "osc-sdk-python/" + VERSION
 
+
 class Authentication:
-    def __init__(self, credentials: Profile, host: str,
-                 method='POST', service='api',
-                 content_type='application/json; charset=utf-8',
-                 algorithm='OSC4-HMAC-SHA256',
-                 signed_headers = 'content-type;host;x-osc-date',
-                 user_agent = DEFAULT_USER_AGENT):
+    def __init__(
+        self,
+        credentials: Profile,
+        host: str,
+        method="POST",
+        service="api",
+        content_type="application/json; charset=utf-8",
+        algorithm="OSC4-HMAC-SHA256",
+        signed_headers="content-type;host;x-osc-date",
+        user_agent=DEFAULT_USER_AGENT,
+    ):
         self.access_key = credentials.access_key
         self.secret_key = credentials.secret_key
         self.login = credentials.login
@@ -31,34 +38,37 @@ def __init__(self, credentials: Profile, host: str,
 
     def forge_headers_signed(self, uri, request_data):
         date_iso, date = self.build_dates()
-        credential_scope = '{}/{}/{}/osc4_request'.format(date, self.region, self.service)
+        credential_scope = "{}/{}/{}/osc4_request".format(
+            date, self.region, self.service
+        )
 
         canonical_request = self.build_canonical_request(date_iso, uri, request_data)
-        str_to_sign = self.create_string_to_sign(date_iso, credential_scope, canonical_request)
+        str_to_sign = self.create_string_to_sign(
+            date_iso, credential_scope, canonical_request
+        )
         signature = self.compute_signature(date, str_to_sign)
         authorisation = self.build_authorization_header(credential_scope, signature)
 
         return {
-            'Content-Type': self.content_type,
-            'X-Osc-Date': date_iso,
-            'Authorization': authorisation,
-            'User-Agent': self.user_agent,
+            "Content-Type": self.content_type,
+            "X-Osc-Date": date_iso,
+            "Authorization": authorisation,
+            "User-Agent": self.user_agent,
         }
 
     def build_dates(self):
-        '''Return YYYYMMDDTHHmmssZ, YYYYMMDD
-        '''
+        """Return YYYYMMDDTHHmmssZ, YYYYMMDD"""
         t = datetime.datetime.now(datetime.timezone.utc)
-        return t.strftime('%Y%m%dT%H%M%SZ'), t.strftime('%Y%m%d')
+        return t.strftime("%Y%m%dT%H%M%SZ"), t.strftime("%Y%m%d")
 
     def sign(self, key, msg):
         return hmac.new(key, msg.encode("utf-8"), hashlib.sha256).digest()
 
     def get_signature_key(self, key, date_stamp_value):
-        k_date = self.sign(('OSC4' + key).encode('utf-8'), date_stamp_value)
+        k_date = self.sign(("OSC4" + key).encode("utf-8"), date_stamp_value)
         k_region = self.sign(k_date, self.region)
         k_service = self.sign(k_region, self.service)
-        k_signing = self.sign(k_service, 'osc4_request')
+        k_signing = self.sign(k_service, "osc4_request")
         return k_signing
 
     def build_canonical_request(self, date_iso, canonical_uri, request_data):
@@ -81,27 +91,46 @@ def build_canonical_request(self, date_iso, canonical_uri, request_data):
         # Step 6: Create payload hash. In this example, the payload (body of
         #         the request) contains the request parameters.
         # Step 7: Combine elements to create canonical request
-        canonical_querystring = ''
-        canonical_headers = 'content-type:' + self.content_type + '\n' \
-                            + 'host:' + self.host + '\n' \
-                            + 'x-osc-date:' + date_iso + '\n'
-        payload_hash = hashlib.sha256(request_data.encode('utf-8')).hexdigest()
-        return self.method + '\n' \
-                    + canonical_uri + '\n' \
-                    + canonical_querystring + '\n' \
-                    + canonical_headers + '\n' \
-                    + self.signed_headers + '\n' \
-                    + payload_hash
+        canonical_querystring = ""
+        canonical_headers = (
+            "content-type:"
+            + self.content_type
+            + "\n"
+            + "host:"
+            + self.host
+            + "\n"
+            + "x-osc-date:"
+            + date_iso
+            + "\n"
+        )
+        payload_hash = hashlib.sha256(request_data.encode("utf-8")).hexdigest()
+        return (
+            self.method
+            + "\n"
+            + canonical_uri
+            + "\n"
+            + canonical_querystring
+            + "\n"
+            + canonical_headers
+            + "\n"
+            + self.signed_headers
+            + "\n"
+            + payload_hash
+        )
 
     def create_string_to_sign(self, date_iso, credential_scope, canonical_request):
         # ************* TASK 2: CREATE THE STRING TO SIGN*************
         # Match the algorithm to the hashing algorithm you use, either SHA-1 or
         # SHA-256 (recommended)
-        return self.algorithm + '\n' \
-                        + date_iso + '\n' \
-                        + credential_scope + '\n' \
-                        + hashlib.sha256(canonical_request.encode('utf-8')).hexdigest()
-
+        return (
+            self.algorithm
+            + "\n"
+            + date_iso
+            + "\n"
+            + credential_scope
+            + "\n"
+            + hashlib.sha256(canonical_request.encode("utf-8")).hexdigest()
+        )
 
     def compute_signature(self, date, string_to_sign):
         # ************* TASK 3: CALCULATE THE SIGNATURE *************
@@ -109,16 +138,27 @@ def compute_signature(self, date, string_to_sign):
         signing_key = self.get_signature_key(self.secret_key, date)
 
         # Sign the string_to_sign using the signing_key
-        return hmac.new(signing_key, string_to_sign.encode('utf-8'),
-                        hashlib.sha256).hexdigest()
-
+        return hmac.new(
+            signing_key, string_to_sign.encode("utf-8"), hashlib.sha256
+        ).hexdigest()
 
     def build_authorization_header(self, credential_scope, signature):
         # ************* TASK 4: ADD SIGNING INFORMATION TO THE REQUEST *************
         # Put the signature information in a header named Authorization.
-        return self.algorithm + ' ' + 'Credential=' + self.access_key + '/' + credential_scope + ', ' \
-            + 'SignedHeaders=' + self.signed_headers + ', ' \
-            + 'Signature=' + signature
+        return (
+            self.algorithm
+            + " "
+            + "Credential="
+            + self.access_key
+            + "/"
+            + credential_scope
+            + ", "
+            + "SignedHeaders="
+            + self.signed_headers
+            + ", "
+            + "Signature="
+            + signature
+        )
 
     def is_basic_auth_configured(self):
         return self.login is not None and self.password is not None
@@ -130,7 +170,7 @@ def get_basic_auth_header(self):
         b64_creds = str(base64.b64encode(creds.encode("utf-8")), "utf-8")
         date_iso, _ = self.build_dates()
         return {
-            'Content-Type': self.content_type,
-            'X-Osc-Date': date_iso,
-            'Authorization': "Basic " + b64_creds
+            "Content-Type": self.content_type,
+            "X-Osc-Date": date_iso,
+            "Authorization": "Basic " + b64_creds,
         }
diff --git a/osc_sdk_python/call.py b/osc_sdk_python/call.py
index b67424b..617d309 100644
--- a/osc_sdk_python/call.py
+++ b/osc_sdk_python/call.py
@@ -6,15 +6,18 @@
 from requests.adapters import HTTPAdapter
 from urllib3.util.retry import Retry
 from urllib3.util import parse_url
+from datetime import timedelta
+from .limiter import RateLimiter
 
 import json
 import warnings
 
-MAX_RETRIES = "3"
+MAX_RETRIES = 3
 RETRY_BACKOFF_FACTOR = "1"
 RETRY_BACKOFF_JITTER = "3"
 RETRY_BACKOFF_MAX = "30"
 
+
 class Call(object):
     def __init__(self, logger=None, limiter=None, **kwargs):
         self.version = kwargs.pop("version", "latest")
@@ -22,13 +25,16 @@ def __init__(self, logger=None, limiter=None, **kwargs):
         self.ssl = kwargs.pop("_ssl", True)
         self.user_agent = kwargs.pop("user_agent", DEFAULT_USER_AGENT)
         self.logger = logger
-        self.limiter = limiter
+        self.limiter: RateLimiter | None = limiter
+        self.adapter = None
+        self.session = Session()
+
         kwargs = self.update_limiter(**kwargs)
         kwargs = self.update_adapter(**kwargs)
         self.update_profile(**kwargs)
-        self.session = Session()
-        self.session.mount("https://", self.adapter)
-        self.session.mount("http://", self.adapter)
+        if self.adapter:
+            self.session.mount("https://", self.adapter)
+            self.session.mount("http://", self.adapter)
 
     def update_credentials(self, **kwargs):
         warnings.warn(
@@ -39,16 +45,29 @@ def update_credentials(self, **kwargs):
         return self.update_profile(**kwargs)
 
     def update_adapter(self, **kwargs):
-        self.adapter = HTTPAdapter(
-            max_retries=Retry(
-                total=int(kwargs.pop("max_retries", MAX_RETRIES)),
-                backoff_factor=float(kwargs.pop("retry_backoff_factor", RETRY_BACKOFF_FACTOR)),
-                backoff_jitter=float(kwargs.pop("retry_backoff_jitter", RETRY_BACKOFF_JITTER)),
-                backoff_max=float(kwargs.pop("retry_backoff_max", RETRY_BACKOFF_MAX)),
-                status_forcelist=(400, 429, 500, 503),
-                allowed_methods=("POST", "GET"),
+        max_retries: int | str | None = kwargs.pop("max_retries", None)
+        if max_retries is not None:
+            max_retries = int(max_retries)
+        else:
+            max_retries = MAX_RETRIES
+
+        if max_retries > 0:
+            self.adapter = HTTPAdapter(
+                max_retries=Retry(
+                    total=max_retries,
+                    backoff_factor=float(
+                        kwargs.pop("retry_backoff_factor", RETRY_BACKOFF_FACTOR)
+                    ),
+                    backoff_jitter=float(
+                        kwargs.pop("retry_backoff_jitter", RETRY_BACKOFF_JITTER)
+                    ),
+                    backoff_max=float(
+                        kwargs.pop("retry_backoff_max", RETRY_BACKOFF_MAX)
+                    ),
+                    status_forcelist=(400, 429, 500, 503),
+                    allowed_methods=("POST", "GET"),
+                )
             )
-        )
         return kwargs
 
     def update_profile(self, **kwargs):
@@ -58,16 +77,13 @@ def update_profile(self, **kwargs):
         self.profile.merge(Profile(**kwargs))
         return kwargs
 
-    def update_limiter(
-        self,
-        **kwargs
-    ):
+    def update_limiter(self, **kwargs):
         limiter_window = kwargs.pop("limiter_window", None)
-        if limiter_window is not None:
-            self.limiter.window = limiter_window
+        if limiter_window is not None and self.limiter is not None:
+            self.limiter.window = timedelta(seconds=int(limiter_window))
 
         limiter_max_requests = kwargs.pop("limiter_max_requests", None)
-        if limiter_max_requests is not None:
+        if limiter_max_requests is not None and self.limiter is not None:
             self.limiter.max_requests = limiter_max_requests
 
         return kwargs
diff --git a/osc_sdk_python/credentials.py b/osc_sdk_python/credentials.py
index 866a44f..7318e7e 100644
--- a/osc_sdk_python/credentials.py
+++ b/osc_sdk_python/credentials.py
@@ -8,8 +8,6 @@
 DEFAULT_PROFILE = "default"
 
 
-
-
 class Endpoint:
     def __init__(self, **kwargs):
         self.api: str = kwargs.pop("api", None)
@@ -102,7 +100,8 @@ def from_env() -> "Profile":
             "x509_client_cert_b64": os.environ.get("OSC_X509_CLIENT_CERT_B64"),
             "x509_client_key": os.environ.get("OSC_X509_CLIENT_KEY"),
             "x509_client_key_b64": os.environ.get("OSC_X509_CLIENT_KEY_B64"),
-            "tls_skip_verify": os.environ.get("OSC_TLS_SKIP_VERIFY", "False").lower() in ("true"),
+            "tls_skip_verify": os.environ.get("OSC_TLS_SKIP_VERIFY", "False").lower()
+            in ("true"),
             "login": os.environ.get("OSC_LOGIN"),
             "password": os.environ.get("OSC_PASSWORD"),
             "protocol": os.environ.get("OSC_PROTOCOL"),
@@ -176,10 +175,12 @@ def from_standard_configuration(path: str, profile: str) -> "Profile":
 
         return merged_profile
 
+
 class Credentials(Profile):
     def __init__(self, **kwargs):
-        warnings.warn("Credentials class is deprecated. Use Profile class instead.",
+        warnings.warn(
+            "Credentials class is deprecated. Use Profile class instead.",
             DeprecationWarning,
-            stacklevel=2
+            stacklevel=2,
         )
-        super().__init__(**kwargs) 
+        super().__init__(**kwargs)
diff --git a/osc_sdk_python/limiter.py b/osc_sdk_python/limiter.py
index cd90bf2..91529f4 100644
--- a/osc_sdk_python/limiter.py
+++ b/osc_sdk_python/limiter.py
@@ -3,13 +3,14 @@
 
 
 class RateLimiter:
-    def __init__(self, window: int, max_requests: int):
-        self.window = window
-        self.max_requests = max_requests
+    def __init__(self, window: timedelta, max_requests: int, datetime_cls=datetime):
+        self.datetime_cls = datetime_cls
+        self.window: timedelta = window
+        self.max_requests: int = max_requests
         self.requests = []
 
     def acquire(self):
-        now = datetime.now(timezone.utc)
+        now = self.datetime_cls.now(timezone.utc)
 
         self.clean_old_requests(now)
 
@@ -18,13 +19,11 @@ def acquire(self):
             wait_time = self.window - (now - oldest)
             time.sleep(wait_time.total_seconds())
 
-            now = datetime.now(timezone.utc)
+            now = self.datetime_cls.now(timezone.utc)
             self.clean_old_requests(now)
 
         self.requests.append(now)
 
     def clean_old_requests(self, now):
-        while len(self.requests) > 0 and self.requests[0] <= now - timedelta(
-            seconds=self.window
-        ):
+        while len(self.requests) > 0 and self.requests[0] <= now - self.window:
             self.requests.pop(0)
diff --git a/osc_sdk_python/outscale_gateway.py b/osc_sdk_python/outscale_gateway.py
index f546fca..bed36f3 100644
--- a/osc_sdk_python/outscale_gateway.py
+++ b/osc_sdk_python/outscale_gateway.py
@@ -5,6 +5,7 @@
 import ruamel.yaml
 from .version import get_version
 import warnings
+from datetime import timedelta
 
 type_mapping = {"boolean": "bool", "string": "str", "integer": "int", "array": "list"}
 
@@ -19,7 +20,7 @@
 LOG_KEEP_ONLY_LAST_REQ = 1
 
 # Default
-DEFAULT_LIMITER_WINDOW = 1  # 1 second
+DEFAULT_LIMITER_WINDOW = timedelta(seconds=1)  # 1 second
 DEFAULT_LIMITER_MAX_REQUESTS = 5  # 5 requests / sec
 
 
@@ -114,7 +115,7 @@ def email(self):
             stacklevel=2,
         )
         return self.login()
-    
+
     def login(self):
         return self.call.profile.login
 
diff --git a/osc_sdk_python/problem.py b/osc_sdk_python/problem.py
index 3f5f652..50ba89e 100644
--- a/osc_sdk_python/problem.py
+++ b/osc_sdk_python/problem.py
@@ -1,5 +1,6 @@
 import json
 
+
 class ProblemDecoder(json.JSONDecoder):
     def decode(self, s):
         data = super().decode(s)
diff --git a/osc_sdk_python/version.py b/osc_sdk_python/version.py
index 2bb9905..4f6025f 100644
--- a/osc_sdk_python/version.py
+++ b/osc_sdk_python/version.py
@@ -1,7 +1,7 @@
 import os
 
+
 def get_version() -> str:
     osc_sdk_python_path = os.path.dirname(os.path.abspath(__file__))
     with open(os.path.join(osc_sdk_python_path, "VERSION"), "r") as fd:
         return fd.read().strip()
-
diff --git a/tests/test_exceptions.py b/tests/test_exceptions.py
index c726c30..ba50fe3 100644
--- a/tests/test_exceptions.py
+++ b/tests/test_exceptions.py
@@ -1,9 +1,11 @@
 import unittest
 import sys
+
 sys.path.append("..")
 from osc_sdk_python import Gateway
 from requests.exceptions import RetryError
 
+
 class TestExcept(unittest.TestCase):
 
     def test_listing(self):
@@ -12,5 +14,6 @@ def test_listing(self):
         with self.assertRaises(RetryError):
             gw.ReadVms(Filters="a")
 
-if __name__ == '__main__':
+
+if __name__ == "__main__":
     unittest.main()
diff --git a/tests/test_limiter.py b/tests/test_limiter.py
new file mode 100644
index 0000000..7eba1b0
--- /dev/null
+++ b/tests/test_limiter.py
@@ -0,0 +1,65 @@
+import datetime
+
+from osc_sdk_python import RateLimiter
+
+i = 0
+
+
+def test_fast(monkeypatch):
+    with monkeypatch.context() as m:
+        was_called = []
+
+        def mock_sleep(t):
+            was_called.append(t)
+            assert t > 0
+            return
+
+        i = 0
+
+        class MockDateTimeFast(datetime.datetime):
+            @classmethod
+            def now(cls, tz=None):
+                global i
+                i += 1
+                return cls(2022, 1, 1, microsecond=i, tzinfo=tz)
+
+        m.setattr("time.sleep", mock_sleep)
+
+        rl = RateLimiter(
+            datetime.timedelta(seconds=1), 5, datetime_cls=MockDateTimeFast
+        )
+        for i in range(10):
+            rl.acquire()
+
+        assert len(rl.requests) > 5
+        assert len(was_called) > 0
+
+
+def test_slow(monkeypatch):
+    with monkeypatch.context() as m:
+        was_called = []
+
+        def mock_sleep(t):
+            was_called.append(t)
+            assert t > 0
+            return
+
+        i = 0
+
+        class MockDateTimeSlow(datetime.datetime):
+            @classmethod
+            def now(cls, tz=None):
+                global i
+                i += 1
+                return cls(2022 + i, 1, 1, tzinfo=tz)
+
+        m.setattr("time.sleep", mock_sleep)
+
+        rl = RateLimiter(
+            datetime.timedelta(seconds=1), 5, datetime_cls=MockDateTimeSlow
+        )
+        for i in range(10):
+            rl.acquire()
+
+        assert len(rl.requests) <= 1
+        assert len(was_called) == 0
diff --git a/tests/test_log.py b/tests/test_log.py
index 1ca8bff..016a365 100644
--- a/tests/test_log.py
+++ b/tests/test_log.py
@@ -1,23 +1,27 @@
 import unittest
 import sys
+
 sys.path.append("..")
 from osc_sdk_python import Gateway, LOG_MEMORY, LOG_KEEP_ONLY_LAST_REQ
 
+
 class TestLog(unittest.TestCase):
 
     def test_listing(self):
         gw = Gateway()
         gw.log.config(type=LOG_MEMORY, what=LOG_KEEP_ONLY_LAST_REQ)
         gw.ReadVms()
-        self.assertEqual(gw.log.str(),
-                         """uri: /api/v1/ReadVms
+        self.assertEqual(
+            gw.log.str(),
+            """uri: /api/v1/ReadVms
 payload:
-{}"""
-                         )
+{}""",
+        )
 
-        gw.ReadVms(Filters={'TagKeys': ['test']})
-        self.assertEqual(gw.log.str(),
-                         """uri: /api/v1/ReadVms
+        gw.ReadVms(Filters={"TagKeys": ["test"]})
+        self.assertEqual(
+            gw.log.str(),
+            """uri: /api/v1/ReadVms
 payload:
 {
   "Filters": {
@@ -25,8 +29,9 @@ def test_listing(self):
       "test"
     ]
   }
-}"""
-                         )
+}""",
+        )
+
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main()
diff --git a/tests/test_manual_aksk.py b/tests/test_manual_aksk.py
index 3eee38f..d148a14 100644
--- a/tests/test_manual_aksk.py
+++ b/tests/test_manual_aksk.py
@@ -1,10 +1,12 @@
 import unittest
 import sys
 import os
+
 sys.path.append("..")
 from osc_sdk_python import Gateway
 import copy
 
+
 class EnvironManager:
     def __enter__(self):
         self.env = copy.deepcopy(os.environ)
@@ -12,6 +14,7 @@ def __enter__(self):
     def __exit__(self, *args):
         os.environ = self.env
 
+
 class TestLoginManualAkSk(unittest.TestCase):
     def test_manual_ak_sk(self):
         with EnvironManager():
@@ -24,5 +27,6 @@ def test_manual_ak_sk(self):
             self.assertIsInstance(volumes, dict)
             self.assertIsInstance(volumes.get("Volumes"), list)
 
-if __name__ == '__main__':
+
+if __name__ == "__main__":
     unittest.main()
diff --git a/tests/test_net.py b/tests/test_net.py
index 2458de9..8055c6f 100644
--- a/tests/test_net.py
+++ b/tests/test_net.py
@@ -1,19 +1,21 @@
 import unittest
 import sys
 import requests
+
 sys.path.append("..")
 from osc_sdk_python import Gateway
 
+
 class TestNet(unittest.TestCase):
     def test_creation_error(self):
         gw = Gateway()
         with self.assertRaises(requests.exceptions.HTTPError) as cm:
-            gw.CreateNet(IpRange='142.42.42.42/32')
+            gw.CreateNet(IpRange="142.42.42.42/32")
 
         e = cm.exception
-        errors = e.response.json().get('Errors')
+        errors = e.response.json().get("Errors")
         self.assertIsNotNone(errors)
         self.assertIsInstance(errors, list)
         for error in errors:
-            code = error.get('Code')
-            self.assertEqual(code, '9050')
+            code = error.get("Code")
+            self.assertEqual(code, "9050")
diff --git a/tests/test_password.py b/tests/test_password.py
index 71e1266..e67457b 100644
--- a/tests/test_password.py
+++ b/tests/test_password.py
@@ -1,10 +1,12 @@
 import unittest
 import sys
 import os
+
 sys.path.append("..")
 from osc_sdk_python import Gateway
 import copy
 
+
 class EnvironManager:
     def __enter__(self):
         self.env = copy.deepcopy(os.environ)
@@ -12,14 +14,18 @@ def __enter__(self):
     def __exit__(self, *args):
         os.environ = self.env
 
+
 class TestLoginPassword(unittest.TestCase):
-    @unittest.skipIf(not (os.environ.get('OSC_TEST_LOGIN') and os.environ.get('OSC_TEST_PASSWORD')), "login/password credentials are not available")
+    @unittest.skipIf(
+        not (os.environ.get("OSC_TEST_LOGIN") and os.environ.get("OSC_TEST_PASSWORD")),
+        "login/password credentials are not available",
+    )
     def test_login(self):
         with EnvironManager():
             os.environ.pop("OSC_ACCESS_KEY", None)
             os.environ.pop("OSC_SECRET_KEY", None)
-            email = os.getenv('OSC_TEST_LOGIN')
-            password = os.getenv('OSC_TEST_PASSWORD')
+            email = os.getenv("OSC_TEST_LOGIN")
+            password = os.getenv("OSC_TEST_PASSWORD")
             self.assertIsNotNone(email, None)
             self.assertIsNotNone(password, None)
             gw = Gateway(email=email, password=password)
@@ -27,5 +33,6 @@ def test_login(self):
             self.assertIsInstance(keys, dict)
             self.assertIsInstance(keys.get("AccessKeys"), list)
 
-if __name__ == '__main__':
+
+if __name__ == "__main__":
     unittest.main()
diff --git a/tests/test_problems.py b/tests/test_problems.py
index fc9d468..adcf094 100644
--- a/tests/test_problems.py
+++ b/tests/test_problems.py
@@ -44,5 +44,5 @@ def test_deserialize_problem2():
                """,
         cls=ProblemDecoder,
     )
-    assert isinstance(obj,Problem)
+    assert isinstance(obj, Problem)
     assert obj.type == "https://example.net/validation-error"
diff --git a/tests/test_vm.py b/tests/test_vm.py
index a9e92b8..bbfc0af 100644
--- a/tests/test_vm.py
+++ b/tests/test_vm.py
@@ -1,8 +1,10 @@
 import unittest
 import sys
+
 sys.path.append("..")
 from osc_sdk_python import Gateway
 
+
 class TestVm(unittest.TestCase):
 
     def test_listing(self):
@@ -10,12 +12,13 @@ def test_listing(self):
         vms = gw.ReadVms()
         self.assertEqual(type(vms), dict)
         self.assertEqual(type(vms.get("Vms")), list)
-    
+
     def test_listing_with_context_manager(self):
         with Gateway() as gw:
             vms = gw.ReadVms()
             self.assertEqual(type(vms), dict)
             self.assertEqual(type(vms.get("Vms")), list)
 
-if __name__ == '__main__':
+
+if __name__ == "__main__":
     unittest.main()
diff --git a/tests/test_volume.py b/tests/test_volume.py
index fb599f9..cc60c62 100644
--- a/tests/test_volume.py
+++ b/tests/test_volume.py
@@ -1,8 +1,10 @@
 import unittest
 import sys
+
 sys.path.append("..")
 from osc_sdk_python import Gateway
 
+
 class TestVolume(unittest.TestCase):
 
     def test_listing(self):
@@ -11,5 +13,6 @@ def test_listing(self):
         self.assertEqual(type(volumes), dict)
         self.assertEqual(type(volumes.get("Volumes")), list)
 
-if __name__ == '__main__':
+
+if __name__ == "__main__":
     unittest.main()