fix: Test case fixes and linting issues

erpnext/patches/v13_0/create_pan_field_for_india.py

@@ -1,4 +1,3 @@
-import frappe
 from frappe.custom.doctype.custom_field.custom_field import create_custom_fields
 
 

erpnext/regional/india/utils.py

@@ -62,7 +62,7 @@ def validate_gstin_for_india(doc, method):
 				.format(doc.gst_state_number), title=_("Invalid GSTIN"))
 
 def validate_pan_for_india(doc, method):
-	if doc.get('country') != 'India' or not doc.pan:
+	if doc.get('country') != 'India' or not doc.get('pan'):
 		return
 
 	if not PAN_NUMBER_FORMAT.match(doc.pan):

erpnext/selling/doctype/customer/customer.json

@@ -212,7 +212,8 @@
    "fieldtype": "Link",
    "ignore_user_permissions": 1,
    "label": "Represents Company",
-   "options": "Company"
+   "options": "Company",
+   "unique": 1
   },
   {
    "depends_on": "represents_company",