Use the raw string notation for regular expression patterns.

Addressing
/tmp/tests/t4_shell.py:26: SyntaxWarning: invalid escape sequence '\['
  self.assertRegex(data, b"^Last login: |\[root@.+ ~\]# $")

.github/workflows/build-test.yaml

@@ -26,4 +26,4 @@ jobs:
       - name: Run tests in the container
         run: docker exec python-libssh python3 setup.py test
       - name: Run tests with installed rpm
-        run: docker exec python-libssh bash -c 'cp -rp tests /tmp/tests && cd /tmp/tests && for i in *.py ; do python3 $i ; done'
+        run: docker exec python-libssh bash -c 'cp -rp tests /tmp/tests && cd /tmp/tests && for i in *.py ; do python3 -Werror $i ; done'

tests/t4_shell.py

@@ -20,15 +20,15 @@ def test1_shell(self):
 		self.assertIsInstance(channel, libssh.Channel)
 
 		data = channel.read_nonblocking()
-		self.assertRegex(data, b"^$|^Last login: ")
+		self.assertRegex(data.decode('utf-8'), r"^$|^Last login: ")
 		sleep(1)
 		data = channel.read_nonblocking()
-		self.assertRegex(data, b"^Last login: |\[root@.+ ~\]# $")
+		self.assertRegex(data.decode('utf-8'), r"^Last login: |\[root@.+ ~\]# $")
 
 		channel.write(b"echo hello world\n")
 		sleep(1)
 		data = channel.read_nonblocking()
-		self.assertRegex(data, b"^echo hello world\r\nhello world\r\n")
+		self.assertRegex(data.decode('utf-8'), r"^echo hello world\r\nhello world\r\n")
 
 		session.disconnect()