refactor: itemgetter instead of assigned lambda
diff --git a/erpnext/stock/report/stock_ageing/stock_ageing.py b/erpnext/stock/report/stock_ageing/stock_ageing.py
index 8a9f0a5..11d50cd 100644
--- a/erpnext/stock/report/stock_ageing/stock_ageing.py
+++ b/erpnext/stock/report/stock_ageing/stock_ageing.py
@@ -4,6 +4,7 @@
 from __future__ import unicode_literals
 import frappe
 from frappe import _
+from operator import itemgetter
 from frappe.utils import date_diff, flt, cint
 from six import iteritems
 from erpnext.stock.doctype.serial_no.serial_no import get_serial_nos
@@ -12,7 +13,7 @@
 	columns = get_columns(filters)
 	item_details = get_fifo_queue(filters)
 	to_date = filters["to_date"]
-	_func = lambda x: x[1]
+	_func = itemgetter(1)
 
 	data = []
 	for item, item_dict in iteritems(item_details):
diff --git a/erpnext/stock/report/stock_balance/stock_balance.py b/erpnext/stock/report/stock_balance/stock_balance.py
index fc3d719..f530ac2 100644
--- a/erpnext/stock/report/stock_balance/stock_balance.py
+++ b/erpnext/stock/report/stock_balance/stock_balance.py
@@ -2,6 +2,7 @@
 # License: GNU General Public License v3. See license.txt
 
 from __future__ import unicode_literals
+from operator import itemgetter
 import frappe, erpnext
 from frappe import _
 from frappe.utils import flt, cint, getdate, now, date_diff
@@ -44,7 +45,7 @@
 	data = []
 	conversion_factors = {}
 
-	_func = lambda x: x[1]
+	_func = itemgetter(1)
 
 	for (company, item, warehouse) in sorted(iwb_map):
 		if item_map.get(item):