added definition and implementation for sma get value when referenced…

… function

src/StockBench/indicators/sma/trigger.py

@@ -51,6 +51,12 @@ def add_to_data_from_rule_value(self, rule_value: str, side: str, data_manager:
         # logic for rule value is the same as the logic for rule key
         return self.add_to_data_from_rule_key(rule_value, None, side, data_manager)
 
+    def get_value_when_referenced(self, rule_value: str, data_manager: DataManager, current_day_index) -> float:
+        """Get the value of the indicator when referenced in a rule value."""
+        # parse rule key will work even when passed a rule value
+        return Trigger._parse_rule_key_no_default_indicator_length(rule_value, self.indicator_symbol, data_manager,
+                                                                   current_day_index)
+
     def check_trigger(self, rule_key, rule_value, data_manager, position, current_day_index) -> bool:
         """Trigger logic for SMA.