diff --git a/erpnext/accounts/doctype/cost_center/cost_center.py b/erpnext/accounts/doctype/cost_center/cost_center.py
index 88d8499..af9c8f7 100644
--- a/erpnext/accounts/doctype/cost_center/cost_center.py
+++ b/erpnext/accounts/doctype/cost_center/cost_center.py
@@ -6,6 +6,8 @@
 from frappe import _
 from frappe.utils import cint, cstr
 from frappe.utils.nestedset import NestedSet
+from erpnext.accounts.utils import validate_field_number
+
 
 class CostCenter(NestedSet):
 	nsm_parent_field = 'parent_cost_center'