code: def format(file_metrics, build_metrics):
      
      def indent(elem, level=0):
          i = "\n" + level*"  "
          if len(elem):
              if not elem.text or not elem.text.strip():
                  elem.text = i + "  "
              if not elem.tail or not elem.tail.strip():
                  elem.tail = i
              for elem in elem:
                  indent(elem, level+1)
              if not elem.tail or not elem.tail.strip():
                  elem.tail = i
          else:
              if level and (not elem.tail or not elem.tail.strip()):
                  elem.tail = i
  
      root = ET.Element('metrics')
  
      # file_metrics
      files = ET.Element('files')
      root.append(files)
  
      for key in file_metrics.keys():
          tmp_file = ET.SubElement(files, "file",
                                   {'name': key, 'language': file_metrics[key]['language']})
          for name in file_metrics[key].keys():
              if name == 'language':
                  continue
              tmp_metric = ET.SubElement(tmp_file, "metric",
                                         {'name': name, 'value': str(file_metrics[key][name])})
  
      # build_metrics
      if build_metrics:
          build = ET.Element('build')
          root.append(build)
          # TODO
  
      indent(root)
      if PY3:
          body = ET.tostring(root, encoding='unicode')
      else:
          body = ET.tostring(root)
      return body
docs: compute output in XML format.