diff --git a/lib/src/dotenv.dart b/lib/src/dotenv.dart
index 1edb454..cd1e788 100644
--- a/lib/src/dotenv.dart
+++ b/lib/src/dotenv.dart
@@ -50,8 +50,10 @@ class DotEnv {
 
   String get(String name, {String? fallback}) {
     final value = maybeGet(name, fallback: fallback);
-    assert(value != null, 'A non-null fallback is required for missing entries');
-    return value!;
+    if(value == null){
+      throw Exception('$name variable not found. A non-null fallback is required for missing entries');
+    }
+    return value;
   }
 
   String? maybeGet(String name, {String? fallback}) => env[name] ?? fallback;