drop python<=3.7 support

According to https://endoflife.date/python python 3.7 has been
EOSed 27 Jun 2023.
Filter all code over `pyupgracde --py38-plus`.

Signed-off-by: Tomasz Kłoczko <kloczek@github.com>

Author: kloczek

docs/conf.py

@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 #
 # Zeep documentation build configuration file, created by
 # sphinx-quickstart on Fri Mar  4 16:51:06 2016.
@@ -52,9 +51,9 @@
 master_doc = 'index'
 
 # General information about the project.
-project = u'Zeep'
-copyright = u'2016, <a href="https://www.mvantellingen.nl/">Michael van Tellingen</a>'
-author = u'Michael van Tellingen'
+project = 'Zeep'
+copyright = '2016, <a href="https://www.mvantellingen.nl/">Michael van Tellingen</a>'
+author = 'Michael van Tellingen'
 
 
 # The version info for the project you're documenting, acts as replacement for
@@ -249,8 +248,8 @@
 # (source start file, target name, title,
 #  author, documentclass [howto, manual, or own class]).
 latex_documents = [
-    (master_doc, 'Zeep.tex', u'Zeep Documentation',
-     u'Michael van Tellingen', 'manual'),
+    (master_doc, 'Zeep.tex', 'Zeep Documentation',
+     'Michael van Tellingen', 'manual'),
 ]
 
 # The name of an image file (relative to this directory) to place at the top of
@@ -293,7 +292,7 @@
 # (source start file, target name, title, author,
 #  dir menu entry, description, category)
 texinfo_documents = [
-    (master_doc, 'Zeep', u'Zeep Documentation',
+    (master_doc, 'Zeep', 'Zeep Documentation',
      author, 'Zeep', 'One line description of project.',
      'Miscellaneous'),
 ]

examples/code39.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 import zeep
 
 client = zeep.Client(

examples/eu_vat_service.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 import zeep
 
 

examples/http_basic_auth.py

@@ -1,5 +1,3 @@
-from __future__ import print_function
-
 from requests import Session
 from requests.auth import HTTPBasicAuth
 

examples/km_to_miles.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 import zeep
 
 

examples/soap_server.py

@@ -21,7 +21,7 @@ class ExampleService(ServiceBase):
     @rpc(Unicode, _returns=Unicode)
     def slow_request(ctx, request_id):
         time.sleep(1)
-        return u'Request: %s' % request_id
+        return 'Request: %s' % request_id
 
 application = Application(
     services=[ExampleService],

src/zeep/__main__.py

@@ -1,5 +1,3 @@
-from __future__ import absolute_import, print_function
-
 import argparse
 import logging
 import logging.config

src/zeep/exceptions.py

@@ -95,7 +95,7 @@ class IncompleteOperation(Error):
 
 class DTDForbidden(Error):
     def __init__(self, name, sysid, pubid):
-        super(DTDForbidden, self).__init__()
+        super().__init__()
         self.name = name
         self.sysid = sysid
         self.pubid = pubid
@@ -107,7 +107,7 @@ def __str__(self):
 
 class EntitiesForbidden(Error):
     def __init__(self, name, content):
-        super(EntitiesForbidden, self).__init__()
+        super().__init__()
         self.name = name
         self.content = content
 

src/zeep/wsdl/attachments.py

@@ -7,10 +7,7 @@
 import base64
 import sys
 
-if sys.version_info >= (3, 8):
-    from functools import cached_property
-else:
-    from cached_property import cached_property
+from functools import cached_property
 
 from requests.structures import CaseInsensitiveDict
 

src/zeep/wsdl/wsdl.py

@@ -3,7 +3,6 @@
     ~~~~~~~~~~~~~~
 
 """
-from __future__ import print_function
 
 import logging
 import operator