diff --git a/.gitignore b/.gitignore
index fa3a7de..8be8af9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -29,6 +29,4 @@ env.bak/
 venv.bak/
 include
 bin/
-lib/
-lib64/
 usr/
diff --git a/src/paysgator/client.py b/src/paysgator/client.py
index a067367..7514e8c 100644
--- a/src/paysgator/client.py
+++ b/src/paysgator/client.py
@@ -6,7 +6,7 @@
     SubscriptionResponse, SubscriptionUpdateRequest, TransactionResponse,
     WalletBalanceResponse
 )
-from .exceptions import AuthenticationError, APIError
+from .exceptions import APIError
 
 class Resource:
     def __init__(self, client):
@@ -66,7 +66,7 @@ def __init__(self, api_key: str):
         self.wallet = Wallet(self)
 
     def set_base_url(self, url: str):
-        self.BASE_URL = url
+self.base_url = url
 
     def request(self, method: str, endpoint: str, data: Optional[dict] = None) -> dict:
         url = f"{self.BASE_URL}{endpoint}"
diff --git a/src/paysgator/models.py b/src/paysgator/models.py
index 8863e2d..0e23852 100644
--- a/src/paysgator/models.py
+++ b/src/paysgator/models.py
@@ -7,10 +7,10 @@ class Mode(str, Enum):
     TEST = "TEST"
 
 class PaymentCreateRequest(BaseModel):
-    amount: float
+    amount: float = Field(..., gt=0)
     currency: str
     external_transaction_id: Optional[str] = Field(None, alias="externalTransactionId")
-    payment_methods: Optional[List[str]] = Field(None, alias="payment_methods")
+    payment_methods: Optional[List[str]] = Field(None)
     fields: Optional[List[str]] = None
     return_url: Optional[str] = Field(None, alias="returnUrl")
     metadata: Optional[Dict[str, Any]] = None
@@ -34,7 +34,7 @@ class Customer(BaseModel):
 class PaymentConfirmRequest(BaseModel):
     payment_link_id: str = Field(..., alias="paymentLinkId")
     payment_method: str = Field(..., alias="paymentMethod")
-    payment_fields: Optional[Dict[str, Any]] = Field(None, alias="payment_fields")
+    payment_fields: Optional[Dict[str, Any]] = Field(None)
     customer: Optional[Customer] = None
 
 class PaymentConfirmResponseData(BaseModel):