Implement fetching account balances

handler/lib/serde/nordigen.py

@@ -82,3 +82,18 @@ class Account(Model):
 
 class AccountDetails(Model):
     account: fields.Nested(Account)
+
+
+class AccountBalanceAmount(Model):
+    amount: fields.Str()
+    currency: fields.Str()
+
+
+class AccountBalances(Model):
+    balanceAmount: fields.Nested(AccountBalanceAmount)
+    balanceType: fields.Str()
+    referenceDate: fields.Date()
+
+
+class AccountBalancesRoot(Model):
+    balances = fields.List(AccountBalances)

handler/lib/serde/truelayer.py

@@ -0,0 +1,14 @@
+from serde import Model, fields
+
+
+class AccountBalances(Model):
+    currency: fields.Str()
+    available: fields.Float()
+    current: fields.Float()
+    overdraft: fields.Float()
+    update_timestamp: fields.DateTime()
+
+
+class AccountBalancesRoot(Model):
+    results: fields.List(AccountBalances)
+    status: fields.Str()