Merge pull request #15650 from rohitwaghchaure/fix_gst_state_issue

[Fix] Nontype object has no attribute gst_state
diff --git a/erpnext/regional/india/utils.py b/erpnext/regional/india/utils.py
index eccce2b..ea600e4 100644
--- a/erpnext/regional/india/utils.py
+++ b/erpnext/regional/india/utils.py
@@ -82,7 +82,7 @@
 
 	if address_name:
 		address = frappe.db.get_value("Address", address_name, ["gst_state", "gst_state_number"], as_dict=1)
-		if address.gst_state and address.gst_state_number:
+		if address and address.gst_state and address.gst_state_number:
 			return cstr(address.gst_state_number) + "-" + cstr(address.gst_state)
 
 def get_regional_address_details(out, doctype, company):