diff --git a/lib/domain/models/basket.dart b/lib/domain/models/basket.dart
index 88a7e22..8f79127 100644
--- a/lib/domain/models/basket.dart
+++ b/lib/domain/models/basket.dart
@@ -28,7 +28,7 @@ class Basket {
         .then((investments) => Future.wait(investments
             .map((investment) => investment.getTotalInvestedAmount())))
         .then((investedAmounts) =>
-            investedAmounts.reduce((value, element) => value + element));
+            investedAmounts.fold(0, (value, element) => value + element));
   }
 
   Future<double> getValue({final bool considerFuturePayments = false}) async {
@@ -38,7 +38,7 @@ class Basket {
             .map((investmentDO) => Investment.from(investmentDO: investmentDO)))
         .then((investments) => Future.wait(investments
             .map((investment) => investment.getValueOn(date: DateTime.now(), considerFuturePayments: considerFuturePayments))))
-        .then((values) => values.reduce((value, element) => value + element));
+        .then((values) => values.fold(0, (value, element) => value + element));
   }
 
   Future<List<Investment>> getInvestments() {
diff --git a/lib/domain/models/goal.dart b/lib/domain/models/goal.dart
index 16393b7..c5a34ee 100644
--- a/lib/domain/models/goal.dart
+++ b/lib/domain/models/goal.dart
@@ -1,5 +1,3 @@
-import 'dart:ffi';
-
 import 'package:wealth_wave/api/apis/goal_investment_api.dart';
 import 'package:wealth_wave/api/apis/investment_api.dart';
 import 'package:wealth_wave/api/db/app_database.dart';
@@ -89,7 +87,7 @@ class Goal {
       {required final int investmentId, required final double split}) async {
     return _goalInvestmentApi
         .create(goalId: id, investmentId: investmentId, split: split)
-        .then((goalInvestmentDO) => Void);
+        .then((goalInvestmentDO) => {});
   }
 
   Future<void> updateTaggedInvestment(
@@ -98,13 +96,13 @@ class Goal {
       required final double split}) async {
     return _goalInvestmentApi
         .update(id: id, goalId: id, investmentId: investmentId, split: split)
-        .then((goalInvestmentDO) => Void);
+        .then((goalInvestmentDO) => {});
   }
 
   Future<void> deleteTaggedInvestment({required final int investmentId}) {
     return _goalInvestmentApi
         .deleteBy(goalId: id, investmentId: investmentId)
-        .then((count) => Void);
+        .then((count) => {});
   }
 
   Future<double> getIRR() async {
diff --git a/lib/domain/models/investment.dart b/lib/domain/models/investment.dart
index 8fce05c..3fa79de 100644
--- a/lib/domain/models/investment.dart
+++ b/lib/domain/models/investment.dart
@@ -1,5 +1,3 @@
-import 'dart:ffi';
-
 import 'package:wealth_wave/api/apis/basket_api.dart';
 import 'package:wealth_wave/api/apis/goal_api.dart';
 import 'package:wealth_wave/api/apis/goal_investment_api.dart';
@@ -166,7 +164,7 @@ class Investment {
   }
 
   Future<void> deleteSIP({required final int sipId}) async {
-    return _sipApi.delete(id: sipId).then((count) => Void);
+    return _sipApi.delete(id: sipId).then((count) => {});
   }
 
   Future<Transaction> createTransaction(
@@ -203,14 +201,14 @@ class Investment {
 
   Future<void> deleteTransaction(
       {required final int id}) async {
-    return _transactionApi.deleteBy(id: id).then((count) => Void);
+    return _transactionApi.deleteBy(id: id).then((count) => {});
   }
 
   Future<void> tagGoal(
       {required final int goalId, required final double split}) async {
     return _goalInvestmentApi
         .create(goalId: goalId, investmentId: id, split: split)
-        .then((goalInvestmentDO) => Void);
+        .then((goalInvestmentDO) => {});
   }
 
   Future<void> updateTaggedGoal(
@@ -219,13 +217,13 @@ class Investment {
       required final double split}) async {
     return _goalInvestmentApi
         .update(id: id, goalId: goalId, investmentId: id, split: split)
-        .then((goalInvestmentDO) => Void);
+        .then((goalInvestmentDO) => {});
   }
 
   Future<void> deleteTaggedGoal({required final int goalId}) {
     return _goalInvestmentApi
         .deleteBy(goalId: goalId, investmentId: id)
-        .then((count) => Void);
+        .then((count) => {});
   }
 
   Future<double> getIRR() async {
diff --git a/lib/domain/models/sip.dart b/lib/domain/models/sip.dart
index 63eb151..add4e36 100644
--- a/lib/domain/models/sip.dart
+++ b/lib/domain/models/sip.dart
@@ -1,5 +1,3 @@
-import 'dart:ffi';
-
 import 'package:wealth_wave/api/apis/investment_api.dart';
 import 'package:wealth_wave/api/apis/transaction_api.dart';
 import 'package:wealth_wave/api/db/app_database.dart';
@@ -94,11 +92,11 @@ class SIP {
   }
 
   Future<void> deleteTransaction({required final int transactionId}) async {
-    return _transactionApi.deleteBy(id: transactionId).then((count) => Void);
+    return _transactionApi.deleteBy(id: transactionId).then((count) => {});
   }
 
   Future<void> deleteTransactions() async {
-    return _transactionApi.deleteBy(sipId: id).then((count) => Void);
+    return _transactionApi.deleteBy(sipId: id).then((count) => {});
   }
 
   static SIP from({required final SipDO sipDO}) {