chore: remove all six compat code

erpnext/buying/doctype/purchase_order/purchase_order_dashboard.py

@@ -1,4 +1,3 @@
-
 from frappe import _
 
 

erpnext/buying/doctype/request_for_quotation/request_for_quotation.py

@@ -12,7 +12,6 @@ from frappe.model.mapper import get_mapped_doc
 from frappe.utils import get_url
 from frappe.utils.print_format import download_pdf
 from frappe.utils.user import get_user_fullname
-from six import string_types
 
 from erpnext.accounts.party import get_party_account_currency, get_party_details
 from erpnext.buying.utils import validate_for_items
@@ -288,7 +287,7 @@ def make_supplier_quotation_from_rfq(source_name, target_doc=None, for_supplier=
 # This method is used to make supplier quotation from supplier's portal.
 @frappe.whitelist()
 def create_supplier_quotation(doc):
-	if isinstance(doc, string_types):
+	if isinstance(doc, str):
 		doc = json.loads(doc)
 
 	try:

erpnext/buying/doctype/request_for_quotation/request_for_quotation_dashboard.py

@@ -1,5 +1,3 @@
-
-
 def get_data():
 	return {
 		'docstatus': 1,

erpnext/buying/doctype/supplier/supplier_dashboard.py

@@ -1,4 +1,3 @@
-
 from frappe import _
 
 

erpnext/buying/doctype/supplier_quotation/supplier_quotation_dashboard.py

@@ -1,4 +1,3 @@
-
 from frappe import _
 
 

erpnext/buying/doctype/supplier_scorecard/supplier_scorecard_dashboard.py

@@ -1,4 +1,3 @@
-
 from frappe import _