Python 3 fixes [merge asap] (#12884)

* Python 3 fixes

* fixed compare

erpnext/controllers/item_variant.py

@@ -7,6 +7,8 @@ from frappe import _
 from frappe.utils import cstr, flt
 import json, copy
 
+from six import string_types
+
 class ItemVariantExistsError(frappe.ValidationError): pass
 class InvalidItemAttributeValueError(frappe.ValidationError): pass
 class ItemTemplateCannotHaveStock(frappe.ValidationError): pass
@@ -26,7 +28,7 @@ def get_variant(template, args=None, variant=None, manufacturer=None,
 		return make_variant_based_on_manufacturer(item_template, manufacturer,
 			manufacturer_part_no)
 	else:
-		if isinstance(args, basestring):
+		if isinstance(args, string_types):
 			args = json.loads(args)
 
 		if not args:
@@ -150,7 +152,7 @@ def find_variant(template, args, variant_item_code=None):
 
 @frappe.whitelist()
 def create_variant(item, args):
-	if isinstance(args, basestring):
+	if isinstance(args, string_types):
 		args = json.loads(args)
 
 	template = frappe.get_doc("Item", item)
@@ -177,7 +179,7 @@ def enqueue_multiple_variant_creation(item, args):
 		item=item, args=args, now=frappe.flags.in_test);
 
 def create_multiple_variants(item, args):
-	if isinstance(args, basestring):
+	if isinstance(args, string_types):
 		args = json.loads(args)
 
 	args_set = generate_keyed_value_combinations(args)

erpnext/controllers/tests/test_item_variant.py

@@ -7,19 +7,10 @@ import unittest
 from erpnext.stock.doctype.item.test_item import set_item_variant_settings
 from erpnext.controllers.item_variant import copy_attributes_to_variant, make_variant_item_code
 
-# python 3 compatibility stuff
-try:
-	unicode = unicode
-except NameError:
-	# Python 3
-	basestring = (str, bytes)
-else:
-	# Python 2
-	basestring = basestring
-
+from six import string_types
 
 def create_variant_with_tables(item, args):
-	if isinstance(args, basestring):
+	if isinstance(args, string_types):
 		args = json.loads(args)
 
 	template = frappe.get_doc("Item", item)