code: def param_help_download(self):
          '''download XML files for parameters'''
          files = []
          for vehicle in ['APMrover2', 'ArduCopter', 'ArduPlane', 'ArduSub', 'AntennaTracker']:
              url = 'http://autotest.ardupilot.org/Parameters/%s/apm.pdef.xml' % vehicle
              path = mp_util.dot_mavproxy("%s.xml" % vehicle)
              files.append((url, path))
              url = 'http://autotest.ardupilot.org/%s-defaults.parm' % vehicle
              if vehicle != 'AntennaTracker':
                  # defaults not generated for AntennaTracker ATM
                  path = mp_util.dot_mavproxy("%s-defaults.parm" % vehicle)
                  files.append((url, path))
          try:
              child = multiproc.Process(target=mp_util.download_files, args=(files,))
              child.start()
          except Exception as e:
              print(ef param_help_download(self):
          '''download XML files for parameters'''
          files = []
          for vehicle in ['APMrover2', 'ArduCopter', 'ArduPlane', 'ArduSub', 'AntennaTracker']:
              url = 'http://autotest.ardupilot.org/Parameters/%s/apm.pdef.xml' % vehicle
              path = mp_util.dot_mavproxy("%s.xml" % vehicle)
              files.append((url, path))
              url = 'http://autotest.ardupilot.org/%s-defaults.parm' % vehicle
              if vehicle != 'AntennaTracker':
                  # defaults not generated for AntennaTracker ATM
                  path = mp_util.dot_mavproxy("%s-defaults.parm" % vehicle)
                  files.append((url, path))
          try:
              child = multiproc.Process(target=mp_util.download_files, args=(files,))
              child.start()
          except Exception as e:
              print(e)
docs: download XML files for parameters