code: def parse_json_body(req):
      
      content_type = req.headers.get("Content-Type")
      if content_type and core.is_json(content_type):
          try:
              return core.parse_json(req.body)
          except TypeError:
              pass
          except json.JSONDecodeError as e:
              if e.doc == "":
                  return core.missing
              else:
                  raise
      return {}
docs: Return the decoded JSON body from the request.