diff --git a/example/pubspec.lock b/example/pubspec.lock
index 7440e0d..f76b1e9 100644
--- a/example/pubspec.lock
+++ b/example/pubspec.lock
@@ -214,4 +214,4 @@ packages:
     version: "2.1.0-nullsafety.5"
 sdks:
   dart: ">=2.12.0-0.0 <3.0.0"
-  flutter: ">=1.22.0 <2.0.0"
+  flutter: ">=1.22.0 <2.0.0"
\ No newline at end of file
diff --git a/lib/src/PointLatLng.dart b/lib/src/PointLatLng.dart
index 3375497..2b0364e 100644
--- a/lib/src/PointLatLng.dart
+++ b/lib/src/PointLatLng.dart
@@ -7,9 +7,7 @@ class PointLatLng {
   /// [longitude].
   ///
   const PointLatLng(double latitude, double longitude)
-      : assert(latitude != null),
-        assert(longitude != null),
-        this.latitude = latitude,
+      : this.latitude = latitude,
         this.longitude = longitude;
 
   /// The latitude in degrees.
diff --git a/lib/src/network_util.dart b/lib/src/network_util.dart
index a37230d..c51b4a5 100644
--- a/lib/src/network_util.dart
+++ b/lib/src/network_util.dart
@@ -48,7 +48,7 @@ class NetworkUtil {
     //String url = uri.toString();
     // print('GOOGLE MAPS URL: ' + url);
     var response = await http.get(uri);
-    if (response?.statusCode == 200) {
+    if (response.statusCode == 200) {
       var parsedJson = json.decode(response.body);
       result.status = parsedJson["status"];
       if (parsedJson["status"]?.toLowerCase() == STATUS_OK &&
diff --git a/lib/src/utils/polyline_result.dart b/lib/src/utils/polyline_result.dart
index 325470a..835b1a0 100644
--- a/lib/src/utils/polyline_result.dart
+++ b/lib/src/utils/polyline_result.dart
@@ -10,7 +10,7 @@ class PolylineResult {
   /// the api status retuned from google api
   ///
   /// returns OK if the api call is successful
-  String status;
+  String? status;
 
   /// list of decoded points
   List<PointLatLng> points;
diff --git a/lib/src/utils/polyline_waypoint.dart b/lib/src/utils/polyline_waypoint.dart
index 5f6aaef..a59b3f1 100644
--- a/lib/src/utils/polyline_waypoint.dart
+++ b/lib/src/utils/polyline_waypoint.dart
@@ -1,5 +1,3 @@
-import 'package:flutter/material.dart';
-
 /// description:
 /// project: flutter_polyline_points
 /// @package:
@@ -19,7 +17,7 @@ class PolylineWayPoint {
   /// which has the effect of splitting the route into two routes
   bool stopOver;
 
-  PolylineWayPoint({@required this.location, this.stopOver = true});
+  PolylineWayPoint({required this.location, this.stopOver = true});
 
   @override
   String toString() {
diff --git a/pubspec.yaml b/pubspec.yaml
index ddeca72..a30eb04 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -4,7 +4,7 @@ version: 0.2.6
 homepage: https://github.com/Dammyololade/flutter_polyline_points
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   flutter:
diff --git a/test/flutter_polyline_points_test.dart b/test/flutter_polyline_points_test.dart
index c0d68aa..117bc40 100644
--- a/test/flutter_polyline_points_test.dart
+++ b/test/flutter_polyline_points_test.dart
@@ -21,7 +21,6 @@ void main() {
         polylinePoints.decodePolyline("_p~iF~ps|U_ulLnnqC_mqNvxq`@");
     print("Answer ---- ");
     print(points);
-    assert(points != null);
     assert(points.length > 0);
   });
 }