fix: improve collateral and debt value calculation with safe token pr…

…ice checks and default rates

apps/shared/loan_entity.py

@@ -45,14 +45,12 @@ def compute_collateral_usd(
         return sum(
             float(token_amount)
             / (10 ** collateral_token_parameters[token].decimals)
-            * (
-                collateral_token_parameters[token].collateral_factor
-                if risk_adjusted
-                else 1.0
-            )
-            * float(collateral_interest_rate_model[token])
-            * prices[collateral_token_parameters[token].underlying_address]
-            for token, token_amount in self.collateral.items()
+            * (collateral_token_parameters[token].collateral_factor if risk_adjusted else 1.0)
+            * float(collateral_interest_rate_model.get(token, 1.0))
+            * prices[underlying_address]
+            for token, token_amount in self.collateral.values.items()
+            if (underlying_address := collateral_token_parameters[token].underlying_address)
+            in prices
         )
 
     def compute_debt_usd(
@@ -74,9 +72,10 @@ def compute_debt_usd(
             float(token_amount)
             / (10 ** debt_token_parameters[token].decimals)
             / (debt_token_parameters[token].debt_factor if risk_adjusted else 1.0)
-            * float(debt_interest_rate_model[token])
-            * prices[debt_token_parameters[token].underlying_address]
-            for token, token_amount in self.debt.items()
+            * float(debt_interest_rate_model.get(token, 1.0))
+            * prices[underlying_address]
+            for token, token_amount in self.debt.values.items()
+            if (underlying_address := debt_token_parameters[token].underlying_address) in prices
         )
 
     @abstractmethod