diff --git a/openmeteo_requests/Client.py b/openmeteo_requests/Client.py
index de632c8..3d74dbc 100644
--- a/openmeteo_requests/Client.py
+++ b/openmeteo_requests/Client.py
@@ -1,4 +1,4 @@
-"""Sync client"""
+"""Open-Meteo API client based on the requests library"""
 
 from __future__ import annotations
 
@@ -13,39 +13,39 @@
 from openmeteo_sdk.WeatherApiResponse import WeatherApiResponse
 
 T = TypeVar("T")
+TSession = TypeVar("TSession", bound=requests.Session)
 
 
-class OpenMeteoRequests(Exception):
-    """Open Meteo Error"""
-
-
-def decode_messages(cls: type[T], data: bytes) -> list[T]:
-    """Decode byte to an array of FlatBuffers messages"""
-    messages = []
-    total = len(data)
-    pos = int(0)
-    while pos < total:
-        length = int.from_bytes(data[pos : pos + 4], byteorder="little")
-        message = cls.GetRootAs(data, pos + 4)
-        messages.append(message)
-        pos += length + 4
-    return messages
+class OpenMeteoRequestsError(Exception):
+    """Open-Meteo Error"""
 
 
 class Client:
-    """Open Meteo Client SYNC"""
+    """Open-Meteo API Client"""
 
-    def __init__(self, session: requests.Session | None = None):
+    def __init__(self, session: TSession | None = None):
         self.session = session or requests.Session()
 
     def _get(self, cls: type[T], url: str, params: any) -> list[T]:
+        params["format"] = "flatbuffers"
+
         response = self.session.get(url, params=params)
         if response.status_code in [400, 429]:
             response_body = response.json()
-            raise OpenMeteoRequests(response_body)
+            raise OpenMeteoRequestsError(response_body)
 
         response.raise_for_status()
-        return decode_messages(cls, response.content)
+
+        data = response.content
+        messages = []
+        total = len(data)
+        pos = int(0)
+        while pos < total:
+            length = int.from_bytes(data[pos : pos + 4], byteorder="little")
+            message = cls.GetRootAs(data, pos + 4)
+            messages.append(message)
+            pos += length + 4
+        return messages
 
     def weather_api(self, url: str, params: any) -> list[WeatherApiResponse]:
         """Get and decode as weather api"""
diff --git a/tests/test_methods.py b/tests/test_methods.py
index 6f81381..e9c068e 100644
--- a/tests/test_methods.py
+++ b/tests/test_methods.py
@@ -17,7 +17,6 @@ def test_fetch_all():
         # 'timezone': 'auto',
         # 'current': ['temperature_2m','precipitation'],
         # 'current_weather': 1,
-        "format": "flatbuffers",
     }
 
     results = om.weather_api("https://archive-api.open-meteo.com/v1/archive", params=params)