fix: cost center in exchange gain loss gl entry
diff --git a/erpnext/controllers/accounts_controller.py b/erpnext/controllers/accounts_controller.py
index 2da63c8..00a2c4c 100644
--- a/erpnext/controllers/accounts_controller.py
+++ b/erpnext/controllers/accounts_controller.py
@@ -714,7 +714,7 @@
 
 					gain_loss_account = frappe.db.get_value('Company', self.company, 'exchange_gain_loss_account')
 					if not gain_loss_account:
-						frappe.throw(_("Please set Default Exchange Gain/Loss Account in Company {}")
+						frappe.throw(_("Please set default Exchange Gain/Loss Account in Company {}")
 							.format(self.get('company')))
 					account_currency = get_account_currency(gain_loss_account)
 					if account_currency != self.company_currency:
@@ -733,7 +733,7 @@
 							"against": party,
 							dr_or_cr + "_in_account_currency": abs(d.exchange_gain_loss),
 							dr_or_cr: abs(d.exchange_gain_loss),
-							"cost_center": self.cost_center,
+							"cost_center": self.cost_center or erpnext.get_default_cost_center(self.company),
 							"project": self.project
 						}, item=d)
 					)