add conditional put

bank/src/account.rs

@@ -1,3 +1,4 @@
+use std::collections::hash_map::DefaultHasher;
 use std::hash::{Hash, Hasher};
 
 use thiserror::Error;
@@ -25,6 +26,23 @@ pub struct Account {
     pub is_active: bool,
 }
 
+impl Account {
+    pub fn hash_string(&self) -> String {
+        let mut hasher = DefaultHasher::new();
+        self.hash(&mut hasher);
+        format!("{:x}", hasher.finish())
+    }
+}
+
+impl Hash for Account {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.number.hash(state);
+        self.owner.hash(state);
+        self.balance.to_string().hash(state);
+        self.is_active.hash(state);
+    }
+}
+
 impl Default for Account {
     fn default() -> Self {
         Account {
@@ -42,12 +60,6 @@ impl PartialEq for Account {
     }
 }
 
-impl Hash for Account {
-    fn hash<H: Hasher>(&self, state: &mut H) {
-        self.number.hash(state);
-    }
-}
-
 impl Account {
     #[cfg(test)]
     pub fn new() -> Self {

bank/src/bank.rs

@@ -13,11 +13,11 @@ impl Bank {
         Default::default()
     }
 
-    pub fn account_action<F: Fn(&mut Account) -> Result<f64, AccountError>>(
+    pub fn account_action<F: Fn(&mut Account) -> Result<R, AccountError>, R>(
         bank: RwLockReadGuard<'_, Bank>,
         nr: &str,
         action: F,
-    ) -> Result<f64, AccountError> {
+    ) -> Result<R, AccountError> {
         match bank.accounts.get(nr) {
             None => Err(AccountError::NotFound),
             Some(account) => {