save before flutter upgrade

lib/models/billing/billing_process.dart

@@ -0,0 +1,34 @@
+import 'dart:convert';
+
+class BillingProcess {
+  BillingProcess({
+    required this.billingProcessId,
+    required this.createdAt,
+    required this.createdBy,
+    required this.status,
+    required this.customersBilled,
+    required this.totalBilled,
+  });
+
+  int billingProcessId;
+  DateTime createdAt;
+  String createdBy;
+  String status;
+  int customersBilled;
+  num totalBilled;
+
+  factory BillingProcess.fromJson(String str) => BillingProcess.fromMap(json.decode(str));
+
+  factory BillingProcess.fromMap(Map<String, dynamic> json) {
+    BillingProcess billingProcess = BillingProcess(
+      billingProcessId: json["billing_process_id"],
+      createdAt: DateTime.parse(json['created_at']),
+      createdBy: json['created_by'],
+      status: json['status'],
+      customersBilled: json['customers_billed'],
+      totalBilled: json['total_billed'],
+    );
+
+    return billingProcess;
+  }
+}