diff --git a/gio/gdbus-2.0/codegen/.flake8 b/gio/gdbus-2.0/codegen/.flake8
new file mode 100644
index 000000000..9450a2832
--- /dev/null
+++ b/gio/gdbus-2.0/codegen/.flake8
@@ -0,0 +1,4 @@
+[flake8]
+# We are generating long lines through templates
+max-line-length = 120
+exclude = __pycache__
diff --git a/gio/gdbus-2.0/codegen/codegen_docbook.py b/gio/gdbus-2.0/codegen/codegen_docbook.py
index b8d683408..b7280e306 100644
--- a/gio/gdbus-2.0/codegen/codegen_docbook.py
+++ b/gio/gdbus-2.0/codegen/codegen_docbook.py
@@ -25,10 +25,6 @@ from os import path
 from . import utils
 
 
-# Disable line length warnings as wrapping the Docbook templates would be hard
-# flake8: noqa: E501
-
-
 # ----------------------------------------------------------------------------------------------------
 
 
@@ -346,7 +342,7 @@ class DocbookCodeGenerator:
     def expand_paras(self, s, expandParamsAndConstants):
         s = self.expand(s, expandParamsAndConstants).strip()
         res = []
-        if not s.startswith("<para"):
+        if not s.startswith("<para>"):
             res.append("<para>")
         for line in s.split("\n"):
             line = line.strip()
diff --git a/gio/gdbus-2.0/codegen/parser.py b/gio/gdbus-2.0/codegen/parser.py
index cf8ea5229..142754739 100644
--- a/gio/gdbus-2.0/codegen/parser.py
+++ b/gio/gdbus-2.0/codegen/parser.py
@@ -77,13 +77,13 @@ class DBusXMLParser:
                     colon_index = line.find(": ")
                     if colon_index == -1:
                         if line.endswith(":"):
-                            symbol = line[0 : len(line) - 1]
+                            symbol = line[0:len(line) - 1]
                             comment_state = DBusXMLParser.COMMENT_STATE_PARAMS
                         else:
                             comment_state = DBusXMLParser.COMMENT_STATE_SKIP
                     else:
                         symbol = line[0:colon_index]
-                        rest_of_line = line[colon_index + 2 :].strip()
+                        rest_of_line = line[colon_index + 2:].strip()
                         if len(rest_of_line) > 0:
                             body += f"{rest_of_line}\n"
                         comment_state = DBusXMLParser.COMMENT_STATE_PARAMS
@@ -98,7 +98,7 @@ class DBusXMLParser:
                         body += f"{orig_line}\n"
                     else:
                         param = line[1:colon_index]
-                        docs = line[colon_index + 2 :]
+                        docs = line[colon_index + 2:]
                         params[param] = docs
                 else:
                     comment_state = DBusXMLParser.COMMENT_STATE_BODY
diff --git a/gio/tests/codegen.py b/gio/tests/codegen.py
index c95736e39..93508fa62 100644
--- a/gio/tests/codegen.py
+++ b/gio/tests/codegen.py
@@ -27,10 +27,10 @@ import subprocess
 import sys
 import tempfile
 import unittest
+import xml.etree.ElementTree as ET
 
 import taptestrunner
 
-
 # Disable line length warnings as wrapping the C code templates would be hard
 # flake8: noqa: E501
 
@@ -625,6 +625,40 @@ G_END_DECLS
         self.assertEqual(result.out.strip().count("GDBusCallFlags call_flags,"), 2)
         self.assertEqual(result.out.strip().count("gint timeout_msec,"), 2)
 
+    def test_generate_valid_docbook(self):
+        """Test the basic functionality of the docbook generator."""
+        xml_contents = """
+        <node>
+          <interface name="org.project.Bar.Frobnicator">
+            <!-- Resize:
+                 @size: New partition size in bytes, 0 for maximal size.
+                 @options: Options.
+                 @since 2.7.2
+
+                 Resizes the partition.
+
+                 The partition will not change its position but might be slightly bigger
+                 than requested due to sector counts and alignment (e.g. 1MiB).
+                 If the requested size can't be allocated it results in an error.
+                 The maximal size can automatically be set by using 0 as size.
+            -->
+            <method name="Resize">
+              <arg name="size" direction="in" type="t"/>
+              <arg name="options" direction="in" type="a{sv}"/>
+            </method>
+          </interface>
+        </node>
+        """
+        res = self.runCodegenWithInterface(
+            xml_contents,
+            "--generate-docbook",
+            "test",
+        )
+        self.assertEqual("", res.err)
+        self.assertEqual("", res.out)
+        with open("test-org.project.Bar.Frobnicator.xml", "r") as f:
+            self.assertTrue(ET.parse(f) is not None)
+
 
 if __name__ == "__main__":
     unittest.main(testRunner=taptestrunner.TAPTestRunner())