chore: Drop dead and deprecated code

* Remove six for PY2 compatability since our dependencies are not, PY2
  is legacy.
* Removed usages of utils from future/past libraries since they are
  deprecated. This includes 'from __future__ ...' and 'from past...'
  statements.
* Removed compatibility imports for PY2, switched from six imports to
  standard library imports.
* Removed utils code blocks that handle operations depending on PY2/3
  versions.
* Removed 'from __future__ ...' lines from templates/code generators
* Used PY3 syntaxes in place of PY2 compatible blocks. eg: metaclass

payments/payment_gateways/doctype/braintree_settings/braintree_settings.py

@@ -2,12 +2,11 @@
 # Copyright (c) 2018, Frappe Technologies and contributors
 # For license information, please see license.txt
 
-from __future__ import unicode_literals
 import frappe
 from frappe.model.document import Document
 import braintree
 from frappe import _
-from six.moves.urllib.parse import urlencode
+from urllib.parse import urlencode
 from frappe.utils import get_url, call_hook_method
 from frappe.integrations.utils import create_request_log, create_payment_gateway
 

payments/payment_gateways/doctype/braintree_settings/test_braintree_settings.py

@@ -1,8 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright (c) 2018, Frappe Technologies and Contributors
 # See license.txt
-from __future__ import unicode_literals
-
 import unittest
 
 class TestBraintreeSettings(unittest.TestCase):

payments/payment_gateways/doctype/paypal_settings/paypal_settings.py

@@ -63,12 +63,11 @@ More Details:
 
 """
 
-from __future__ import unicode_literals
 import frappe
 import json
 import pytz
 from frappe import _
-from six.moves.urllib.parse import urlencode
+from urllib.parse import urlencode
 from frappe.model.document import Document
 from frappe.integrations.utils import create_request_log, make_post_request, create_payment_gateway
 from frappe.utils import get_url, call_hook_method, cint, get_datetime

payments/payment_gateways/doctype/paytm_settings/paytm_settings.py

@@ -2,10 +2,9 @@
 # Copyright (c) 2020, Frappe Technologies and contributors
 # For license information, please see license.txt
 
-from __future__ import unicode_literals
 import json
 import requests
-from six.moves.urllib.parse import urlencode
+from urllib.parse import urlencode
 
 import frappe
 from frappe.model.document import Document
@@ -59,7 +58,7 @@ def get_paytm_params(payment_details, order_id, paytm_config):
 
 	# initialize a dictionary
 	paytm_params = dict()
-	
+
 	redirect_uri = get_request_site_address(True) + "/api/method/frappe.integrations.doctype.paytm_settings.paytm_settings.verify_transaction"
 
 

payments/payment_gateways/doctype/paytm_settings/test_paytm_settings.py

@@ -1,8 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright (c) 2020, Frappe Technologies and Contributors
 # See license.txt
-from __future__ import unicode_literals
-
 # import frappe
 import unittest
 

payments/payment_gateways/doctype/razorpay_settings/razorpay_settings.py

@@ -60,14 +60,13 @@ For razorpay payment status is Authorized
 
 """
 
-from __future__ import unicode_literals
 import frappe
 from frappe import _
 import json
 import hmac
 import razorpay
 import hashlib
-from six.moves.urllib.parse import urlencode
+from urllib.parse import urlencode
 from frappe.model.document import Document
 from frappe.utils import get_url, call_hook_method, cint, get_timestamp
 from frappe.integrations.utils import (make_get_request, make_post_request, create_request_log,

payments/payment_gateways/doctype/stripe_settings/stripe_settings.py

@@ -2,11 +2,10 @@
 # Copyright (c) 2017, Frappe Technologies and contributors
 # For license information, please see license.txt
 
-from __future__ import unicode_literals
 import frappe
 from frappe.model.document import Document
 from frappe import _
-from six.moves.urllib.parse import urlencode
+from urllib.parse import urlencode
 from frappe.utils import get_url, call_hook_method, cint, flt
 from frappe.integrations.utils import make_get_request, make_post_request, create_request_log, create_payment_gateway
 

payments/payment_gateways/doctype/stripe_settings/test_stripe_settings.py

@@ -1,8 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright (c) 2018, Frappe Technologies and Contributors
 # See license.txt
-from __future__ import unicode_literals
-
 import unittest
 
 class TestStripeSettings(unittest.TestCase):

payments/payments/doctype/payment_gateway/payment_gateway.py

@@ -2,7 +2,6 @@
 # Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and contributors
 # For license information, please see license.txt
 
-from __future__ import unicode_literals
 import frappe
 from frappe.model.document import Document
 

payments/payments/doctype/payment_gateway/test_payment_gateway.py

@@ -1,8 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
 # See license.txt
-from __future__ import unicode_literals
-
 import frappe
 import unittest
 

payments/templates/pages/braintree_checkout.py

@@ -1,6 +1,5 @@
 # Copyright (c) 2018, Frappe Technologies Pvt. Ltd. and Contributors
 # License: GNU General Public License v3. See license.txt
-from __future__ import unicode_literals
 import frappe
 from frappe import _
 from frappe.utils import flt

payments/templates/pages/payment_cancel.py

@@ -1,7 +1,6 @@
 # Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
 # See license.txt
 
-from __future__ import unicode_literals
 import frappe
 
 def get_context(context):

payments/templates/pages/payment_success.py

@@ -1,8 +1,6 @@
 # Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
 # See license.txt
 
-from __future__ import unicode_literals
-
 import frappe
 no_cache = True
 

payments/templates/pages/paytm_checkout.py

@@ -1,6 +1,5 @@
 # Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
 # License: GNU General Public License v3. See license.txt
-from __future__ import unicode_literals
 import frappe
 from frappe import _
 import json

payments/templates/pages/razorpay_checkout.py

@@ -1,11 +1,9 @@
 # Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
 # License: GNU General Public License v3. See license.txt
-from __future__ import unicode_literals
 import frappe
 from frappe import _
 from frappe.utils import flt, cint
 import json
-from six import string_types
 
 no_cache = 1
 
@@ -47,7 +45,7 @@ def get_api_key():
 def make_payment(razorpay_payment_id, options, reference_doctype, reference_docname, token):
 	data = {}
 
-	if isinstance(options, string_types):
+	if isinstance(options, str):
 		data = json.loads(options)
 
 	data.update({

payments/templates/pages/stripe_checkout.py

@@ -1,6 +1,5 @@
 # Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
 # License: GNU General Public License v3. See license.txt
-from __future__ import unicode_literals
 import frappe
 from frappe import _
 from frappe.utils import cint, fmt_money