code: def resolve(self, context, quiet=True):
          
          try:
              obj = context
              for level in self.levels:
                  if isinstance(obj, dict):
                      obj = obj[level]
                  elif isinstance(obj, list) or isinstance(obj, tuple):
                      obj = obj[int(level)]
                  else:
                      if callable(getattr(obj, level)):
                          try:
                              obj = getattr(obj, level)()
                          except KeyError:
                              obj = getattr(obj, level)
                      else:
                          # for model field that has choice set
                          # use get_xxx_display to access
                          display = 'get_%s_display' % level
                          obj = getattr(obj, display)() if hasattr(obj, display) else getattr(obj, level)
                  if not obj:
                      break
              return obj
          except Exception as e:
              if quiet:
                  return ''
              else:
                  raise e
docs: Return an object described by the accessor by traversing the attributes
          of context.