Add YearMonthRange helper to YearMonth module

src/shared_api_lib/src/year_month.rs

@@ -104,3 +104,47 @@ impl PartialOrd for YearMonth {
             .is_some_and(std::cmp::Ordering::is_ge)
     }
 }
+
+// Bounds are inclusive
+pub struct YearMonthRange {
+    start: YearMonth,
+    current: YearMonth,
+    stop: YearMonth,
+}
+
+impl YearMonthRange {
+    // Bounds are inclusive
+    pub fn new(start: &YearMonth, stop: &YearMonth) -> Result<YearMonthRange, &'static str> {
+        if *start > *stop {
+            return Err("Start cannot be greater than stop");
+        }
+
+        return Ok(YearMonthRange {
+            start: start.clone(),
+            current: start.clone(),
+            stop: stop.clone(),
+        });
+    }
+
+    pub fn start(&self) -> YearMonth {
+        self.start.clone()
+    }
+
+    pub fn stop(&self) -> YearMonth {
+        self.stop.clone()
+    }
+}
+
+impl Iterator for YearMonthRange {
+    type Item = YearMonth;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.current > self.stop {
+            None
+        } else {
+            let result = self.current.clone();
+            self.current = result.get_next_month();
+            Some(result)
+        }
+    }
+}