[single_assessment] feat: add a base class for prediction evaluation

climate_health/single_assessment/prediction_evaluator.py

@@ -0,0 +1,17 @@
+from sklearn.metrics import mean_squared_error, mean_absolute_error, r2_score
+
+class PredictionsEvaluator:
+    def __init__(self, predictions, ground_truths):
+        self.predictions = predictions
+        self.ground_truths = ground_truths
+        self.metrics = self._evaluate_predictions()
+
+    def _evaluate_predictions(self):
+        metrics = {}
+        metrics['mse'] = mean_squared_error(self.ground_truths, self.predictions)
+        metrics['mae'] = mean_absolute_error(self.ground_truths, self.predictions)
+        metrics['r2'] = r2_score(self.ground_truths, self.predictions)
+        return metrics
+
+    def get_metrics(self):
+        return self.metrics