diff --git a/pyproject.toml b/pyproject.toml
index 4a9a2eb..c0b8250 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -98,7 +98,6 @@ extend-safe-fixes = [
     "D415", # docstrings should end with a period, question mark, or exclamation point
 ]
 ignore = [
-    "ANN204",
     "ANN401",
     "ARG002",
     "B006",
diff --git a/src/multisafepay/api/base/abstract_manager.py b/src/multisafepay/api/base/abstract_manager.py
index 6503ffd..52981d9 100644
--- a/src/multisafepay/api/base/abstract_manager.py
+++ b/src/multisafepay/api/base/abstract_manager.py
@@ -19,7 +19,7 @@ class AbstractManager:
 
     """
 
-    def __init__(self: "AbstractManager", client: Client):
+    def __init__(self: "AbstractManager", client: Client) -> None:
         """
         Initialize the AbstractManager with a Client instance.
 
diff --git a/src/multisafepay/api/base/listings/listing.py b/src/multisafepay/api/base/listings/listing.py
index 07a23fa..ba3d736 100644
--- a/src/multisafepay/api/base/listings/listing.py
+++ b/src/multisafepay/api/base/listings/listing.py
@@ -5,7 +5,7 @@
 
 # See the DISCLAIMER.md file for disclaimer details.
 
-from typing import Any, Dict, Generic, List, TypeVar
+from typing import Any, Dict, Generic, Iterator, List, TypeVar
 
 from pydantic.main import BaseModel
 
@@ -29,7 +29,7 @@ def __init__(
         data: List[Any],
         class_type: type,
         **kwargs: Dict[str, Any],
-    ):
+    ) -> None:
         """
         Initialize the Listing with data and a class type.
 
@@ -53,7 +53,7 @@ def __init__(
 
         super().__init__(data=elements)
 
-    def __iter__(self: "Listing"):
+    def __iter__(self: "Listing") -> Iterator[T]:
         """
         Return an iterator over the items in the listing.
 
@@ -79,7 +79,7 @@ def __getitem__(self: "Listing", index: int) -> T:
         """
         return self.data[index]
 
-    def __len__(self: "Listing"):
+    def __len__(self: "Listing") -> int:
         """
         Get the number of items in the listing.
 
diff --git a/src/multisafepay/api/base/listings/listing_pager.py b/src/multisafepay/api/base/listings/listing_pager.py
index 09f9a4e..f2373e2 100644
--- a/src/multisafepay/api/base/listings/listing_pager.py
+++ b/src/multisafepay/api/base/listings/listing_pager.py
@@ -28,7 +28,7 @@ def __init__(
         data: list,
         pager: Optional[Pager],
         class_type: type,
-    ):
+    ) -> None:
         """
         Initialize the ListingPager with data, pager, and class type.
 
diff --git a/src/multisafepay/api/base/response/custom_api_response.py b/src/multisafepay/api/base/response/custom_api_response.py
index e6bc406..0a9398d 100644
--- a/src/multisafepay/api/base/response/custom_api_response.py
+++ b/src/multisafepay/api/base/response/custom_api_response.py
@@ -26,7 +26,7 @@ def __init__(
         self: "CustomApiResponse",
         data: Optional[Any],
         **kwargs: Dict[str, Any],
-    ):
+    ) -> None:
         """
         Initialize the CustomApiResponse with optional data and additional keyword arguments.
 
diff --git a/src/multisafepay/api/paths/auth/auth_manager.py b/src/multisafepay/api/paths/auth/auth_manager.py
index 0f97578..d7e1324 100644
--- a/src/multisafepay/api/paths/auth/auth_manager.py
+++ b/src/multisafepay/api/paths/auth/auth_manager.py
@@ -22,7 +22,7 @@ class AuthManager(AbstractManager):
     A manager class for handling authentication-related operations.
     """
 
-    def __init__(self: "AuthManager", client: Client):
+    def __init__(self: "AuthManager", client: Client) -> None:
         """
         Initialize the CaptureManager with a client.
 
diff --git a/src/multisafepay/api/paths/capture/capture_manager.py b/src/multisafepay/api/paths/capture/capture_manager.py
index 8bd7306..1837f27 100644
--- a/src/multisafepay/api/paths/capture/capture_manager.py
+++ b/src/multisafepay/api/paths/capture/capture_manager.py
@@ -26,7 +26,7 @@ class CaptureManager(AbstractManager):
     A class to manage capture operations.
     """
 
-    def __init__(self: "CaptureManager", client: Client):
+    def __init__(self: "CaptureManager", client: Client) -> None:
         """
         Initialize the CaptureManager with a client.
 
diff --git a/src/multisafepay/api/paths/categories/category_manager.py b/src/multisafepay/api/paths/categories/category_manager.py
index 25dc00e..c1681bd 100644
--- a/src/multisafepay/api/paths/categories/category_manager.py
+++ b/src/multisafepay/api/paths/categories/category_manager.py
@@ -20,7 +20,7 @@ class CategoryManager(AbstractManager):
     A manager class for handling category-related API requests.
     """
 
-    def __init__(self: "CategoryManager", client: Client):
+    def __init__(self: "CategoryManager", client: Client) -> None:
         """
         Initialize the CategoryManager with a client.
 
diff --git a/src/multisafepay/api/paths/gateways/gateway_manager.py b/src/multisafepay/api/paths/gateways/gateway_manager.py
index c73547e..fe427f2 100644
--- a/src/multisafepay/api/paths/gateways/gateway_manager.py
+++ b/src/multisafepay/api/paths/gateways/gateway_manager.py
@@ -28,7 +28,7 @@ class GatewayManager(AbstractManager):
     Manages gateway-related operations.
     """
 
-    def __init__(self: "GatewayManager", client: Client):
+    def __init__(self: "GatewayManager", client: Client) -> None:
         """
         Initialize the CategoryManager with a client.
 
diff --git a/src/multisafepay/api/paths/issuers/issuer_manager.py b/src/multisafepay/api/paths/issuers/issuer_manager.py
index d374c42..cf630f6 100644
--- a/src/multisafepay/api/paths/issuers/issuer_manager.py
+++ b/src/multisafepay/api/paths/issuers/issuer_manager.py
@@ -24,7 +24,7 @@ class IssuerManager(AbstractManager):
     Manager class for handling issuer-related operations.
     """
 
-    def __init__(self: "IssuerManager", client: Client):
+    def __init__(self: "IssuerManager", client: Client) -> None:
         """
         Initialize the IssuerManager with a client.
 
diff --git a/src/multisafepay/api/paths/me/me_manager.py b/src/multisafepay/api/paths/me/me_manager.py
index 302e859..1d22cc5 100644
--- a/src/multisafepay/api/paths/me/me_manager.py
+++ b/src/multisafepay/api/paths/me/me_manager.py
@@ -21,7 +21,7 @@ class MeManager(AbstractManager):
     A manager class for handling 'me' related API requests.
     """
 
-    def __init__(self: "MeManager", client: Client):
+    def __init__(self: "MeManager", client: Client) -> None:
         """
         Initialize the MeManager with a client.
 
diff --git a/src/multisafepay/api/paths/orders/order_manager.py b/src/multisafepay/api/paths/orders/order_manager.py
index 209c8fd..eeefcfd 100644
--- a/src/multisafepay/api/paths/orders/order_manager.py
+++ b/src/multisafepay/api/paths/orders/order_manager.py
@@ -48,7 +48,7 @@ class OrderManager(AbstractManager):
     Manages operations related to orders, such as creating, updating, capturing, and refunding orders.
     """
 
-    def __init__(self: "OrderManager", client: Client):
+    def __init__(self: "OrderManager", client: Client) -> None:
         """
         Initialize the OrderManager with a client.
 
diff --git a/src/multisafepay/api/paths/payment_methods/payment_method_manager.py b/src/multisafepay/api/paths/payment_methods/payment_method_manager.py
index eb22307..31bc140 100644
--- a/src/multisafepay/api/paths/payment_methods/payment_method_manager.py
+++ b/src/multisafepay/api/paths/payment_methods/payment_method_manager.py
@@ -30,7 +30,7 @@ class PaymentMethodManager(AbstractManager):
     A class representing the PaymentMethodManager.
     """
 
-    def __init__(self: "PaymentMethodManager", client: Client):
+    def __init__(self: "PaymentMethodManager", client: Client) -> None:
         """
         Initialize the CaptureManager with a client.
 
diff --git a/src/multisafepay/api/paths/recurring/recurring_manager.py b/src/multisafepay/api/paths/recurring/recurring_manager.py
index 4c898e3..61e8329 100644
--- a/src/multisafepay/api/paths/recurring/recurring_manager.py
+++ b/src/multisafepay/api/paths/recurring/recurring_manager.py
@@ -35,7 +35,7 @@ class RecurringManager(AbstractManager):
     CREDIT_CARD_GATEWAY_CODE = "CREDITCARD"
     CREDIT_CARD_GATEWAYS = ["VISA", "MASTERCARD", "AMEX", "MAESTRO"]
 
-    def __init__(self: "RecurringManager", client: Client):
+    def __init__(self: "RecurringManager", client: Client) -> None:
         """
         Initializes the RecurringManager with a client.
 
diff --git a/src/multisafepay/api/paths/transactions/transaction_manager.py b/src/multisafepay/api/paths/transactions/transaction_manager.py
index b1f4d00..90098d0 100644
--- a/src/multisafepay/api/paths/transactions/transaction_manager.py
+++ b/src/multisafepay/api/paths/transactions/transaction_manager.py
@@ -41,7 +41,7 @@ class TransactionManager(AbstractManager):
     A class representing the TransactionManager.
     """
 
-    def __init__(self: "TransactionManager", client: Client):
+    def __init__(self: "TransactionManager", client: Client) -> None:
         """
         Initialize the CaptureManager with a client.
 
diff --git a/src/multisafepay/client/client.py b/src/multisafepay/client/client.py
index dc62ce9..ee5047e 100644
--- a/src/multisafepay/client/client.py
+++ b/src/multisafepay/client/client.py
@@ -45,7 +45,7 @@ def __init__(
         is_production: bool,
         http_client: Optional[Session] = None,
         locale: str = "en_US",
-    ):
+    ) -> None:
         """
         Initialize the Client.
 
diff --git a/src/multisafepay/exception/api.py b/src/multisafepay/exception/api.py
index 7692d93..34706df 100644
--- a/src/multisafepay/exception/api.py
+++ b/src/multisafepay/exception/api.py
@@ -21,7 +21,11 @@ class ApiException(Exception):
 
     """
 
-    def __init__(self: "ApiException", message: str, context: dict = {}):
+    def __init__(
+        self: "ApiException",
+        message: str,
+        context: dict = {},
+    ) -> None:
         """
         Initialize the ApiException.
 
diff --git a/src/multisafepay/sdk.py b/src/multisafepay/sdk.py
index f796336..0208129 100644
--- a/src/multisafepay/sdk.py
+++ b/src/multisafepay/sdk.py
@@ -40,7 +40,7 @@ def __init__(
         is_production: bool,
         http_client: Optional[Client] = None,
         locale: str = "en_US",
-    ):
+    ) -> None:
         """
         Initialize the SDK with the provided configuration.
 
diff --git a/src/multisafepay/util/message.py b/src/multisafepay/util/message.py
index f0b2bad..e657336 100644
--- a/src/multisafepay/util/message.py
+++ b/src/multisafepay/util/message.py
@@ -6,7 +6,7 @@
 # See the DISCLAIMER.md file for disclaimer details.
 
 
-from typing import Dict, List
+from typing import Dict, Iterator, List
 
 from pydantic import BaseModel, Field
 
@@ -36,7 +36,7 @@ class MessageList(BaseModel):
 
     __root__: List[Message] = Field(default_factory=list)
 
-    def __iter__(self: "MessageList"):
+    def __iter__(self: "MessageList") -> Iterator[Message]:
         """
         Iterate over the messages in the list.
 
@@ -47,7 +47,7 @@ def __iter__(self: "MessageList"):
         """
         return iter(self.__root__)
 
-    def __getitem__(self: "MessageList", index: int):
+    def __getitem__(self: "MessageList", index: int) -> "Message":
         """
         Get a message by index.
 
@@ -62,7 +62,7 @@ def __getitem__(self: "MessageList", index: int):
         """
         return self.__root__[index]
 
-    def __len__(self: "MessageList"):
+    def __len__(self: "MessageList") -> int:
         """
         Get the number of messages in the list.
 
diff --git a/src/multisafepay/value_object/date.py b/src/multisafepay/value_object/date.py
index aaec5d8..a6c2eee 100644
--- a/src/multisafepay/value_object/date.py
+++ b/src/multisafepay/value_object/date.py
@@ -26,7 +26,7 @@ class Date(InmutableModel):
     timestamp: float
     str_date: str
 
-    def __init__(self: "Date", date: str):
+    def __init__(self: "Date", date: str) -> None:
         """
         Initialize a Date object.
 
diff --git a/tests/multisafepay/integration/api/base/listings/test_integration_listing_pager.py b/tests/multisafepay/integration/api/base/listings/test_integration_listing_pager.py
index bdd0238..60304ed 100644
--- a/tests/multisafepay/integration/api/base/listings/test_integration_listing_pager.py
+++ b/tests/multisafepay/integration/api/base/listings/test_integration_listing_pager.py
@@ -14,7 +14,7 @@
 
 
 class MockItem:
-    def __init__(self: "MockItem", value: Any):
+    def __init__(self: "MockItem", value: Any) -> None:
         """
         Initialize a MockItem with a given value.
 
diff --git a/tests/multisafepay/unit/api/base/listings/test_unit_listing.py b/tests/multisafepay/unit/api/base/listings/test_unit_listing.py
index abb3975..ad6f7d5 100644
--- a/tests/multisafepay/unit/api/base/listings/test_unit_listing.py
+++ b/tests/multisafepay/unit/api/base/listings/test_unit_listing.py
@@ -11,7 +11,7 @@
 
 
 class MockItem:
-    def __init__(self: "MockItem", value: Any):
+    def __init__(self: "MockItem", value: Any) -> None:
         self.value = value
 
 
diff --git a/tests/multisafepay/unit/api/base/listings/test_unit_listing_pager.py b/tests/multisafepay/unit/api/base/listings/test_unit_listing_pager.py
index b42dd99..844c54d 100644
--- a/tests/multisafepay/unit/api/base/listings/test_unit_listing_pager.py
+++ b/tests/multisafepay/unit/api/base/listings/test_unit_listing_pager.py
@@ -11,7 +11,7 @@
 
 
 class MockItem:
-    def __init__(self: "MockItem", value: Any):
+    def __init__(self: "MockItem", value: Any) -> None:
         """
         Initialize a MockItem with a given value.