diff --git a/erpnext/stock/doctype/material_request/material_request.py b/erpnext/stock/doctype/material_request/material_request.py
index 9187b78..4450af7 100644
--- a/erpnext/stock/doctype/material_request/material_request.py
+++ b/erpnext/stock/doctype/material_request/material_request.py
@@ -174,9 +174,7 @@
 		
 		for d in bean.doclist.get({"parentfield": "mtn_details"}):
 			if d.material_request:
-				if d.material_request not in material_request_map:
-					material_request_map[d.material_request] = []):
-				material_request_map[d.material_request].append(d.material_request_item)
+				material_request_map.setdefault(d.material_request, []).append(d.material_request_item)
 			
 		for mr_name, mr_items in material_request_map.items():
 			mr_obj = webnotes.get_obj("Material Request", mr_name, with_children=1)
@@ -369,4 +367,4 @@
 		}
 	}, target_doclist, set_missing_values)
 
-	return [d.fields for d in doclist]
\ No newline at end of file
+	return [d.fields for d in doclist]