Add __iter__ to Aggify

Author: mohamadkhalaj

aggify/aggify.py

@@ -61,6 +61,10 @@ def __init__(self, base_model: Type[Document]):
         self.stop = None
         self.q = None
 
+    def __iter__(self):
+        # Return a generator or iterator for the data you want to represent as a list
+        return iter(self.pipelines)
+
     @last_out_stage_check
     def project(self, **kwargs: QueryParams) -> "Aggify":
         """