tools: Modernize generate-docs-nm-settings-docs-gir.py to 2022 standards

* Create main() function and put its execution under
  __name__ == '__main__' guard.
* Only one module import per line
* Use required=True to check if necessary arguments have
  been passed.
* Remove usage() as ArgumentParser handles that already

tools/generate-docs-nm-settings-docs-gir.py

@@ -3,16 +3,16 @@
 #
 # Copyright (C) 2009 - 2017 Red Hat, Inc.
 #
-
-from __future__ import print_function
-
+from __future__ import print_function, unicode_literals
+import argparse
 import os
 import gi
 import xml.sax.saxutils as saxutils
+import re
 
 gi.require_version("GIRepository", "2.0")
 from gi.repository import GIRepository
-import argparse, re, sys
+
 import xml.etree.ElementTree as ET
 
 try:
@@ -190,32 +190,9 @@ def xml_quoteattr(val):
     return saxutils.quoteattr(str(val))
 
 
-def usage():
-    print("Usage: %s --gir FILE --output FILE" % sys.argv[0])
-    exit()
-
-
-parser = argparse.ArgumentParser()
-parser.add_argument(
-    "-l",
-    "--lib-path",
-    metavar="PATH",
-    action="append",
-    help="path to scan for shared libraries",
-)
-parser.add_argument("-g", "--gir", metavar="FILE", help="NM-1.0.gir file")
-parser.add_argument("-o", "--output", metavar="FILE", help="output file")
-
-args = parser.parse_args()
-if args.gir is None or args.output is None:
-    usage()
-
-if args.lib_path:
-    for lib in args.lib_path:
-        GIRepository.Repository.prepend_library_path(lib)
-
-girxml = ET.parse(args.gir).getroot()
-outfile = open(args.output, mode="w")
+def main(gir_path_str, output_path_str):
+    girxml = ET.parse(gir_path_str).getroot()
+    outfile = open(output_path_str, mode="w")
 
     basexml = girxml.find('./gi:namespace/gi:class[@name="Setting"]', ns_map)
     settings = girxml.findall('./gi:namespace/gi:class[@parent="Setting"]', ns_map)
@@ -247,7 +224,8 @@ for settingxml in settings:
         class_desc = get_docs(settingxml)
         if class_desc is None:
             raise Exception(
-            "%s needs a gtk-doc block with one-line description" % setting.props.name
+                "%s needs a gtk-doc block with one-line description"
+                % setting.props.name
             )
         outfile.write(
             '  <setting name="%s" description=%s name_upper="%s" >\n'
@@ -281,7 +259,8 @@ for settingxml in settings:
 
             if value_desc is None:
                 raise Exception(
-                "%s.%s needs a documentation description" % (setting.props.name, prop)
+                    "%s.%s needs a documentation description"
+                    % (setting.props.name, prop)
                 )
 
             default_value_as_xml = ""
@@ -303,3 +282,36 @@ for settingxml in settings:
 
     outfile.write("</nm-setting-docs>\n")
     outfile.close()
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "-l",
+        "--lib-path",
+        metavar="PATH",
+        action="append",
+        help="path to scan for shared libraries",
+    )
+    parser.add_argument(
+        "-g",
+        "--gir",
+        metavar="FILE",
+        help="NM-1.0.gir file",
+        required=True,
+    )
+    parser.add_argument(
+        "-o",
+        "--output",
+        metavar="FILE",
+        help="output file",
+        required=True,
+    )
+
+    args = parser.parse_args()
+
+    if args.lib_path:
+        for lib in args.lib_path:
+            GIRepository.Repository.prepend_library_path(lib)
+
+    main(args.gir, args.output)