      def _get_request_body(self, path, method):
          if method not in ('PUT', 'PATCH', 'POST'):
              return {}
  
          serializer = self._get_serializer(path, method)
  
          if not isinstance(serializer, serializers.Serializer):
              return {}
  
 
</s> remove                 for ct in self.content_types
 </s> add                 for ct in self.request_media_types </s> remove                     for ct in self.content_types
 </s> add                     for ct in self.response_media_types
        self.request_media_types = self.map_parsers(path, method)

      def _get_request_body(self, path, method):
          if method not in ('PUT', 'PATCH', 'POST'):
              return {}
  
        self.request_media_types = self.map_parsers(path, method)

          serializer = self._get_serializer(path, method)
  
          if not isinstance(serializer, serializers.Serializer):
              return {}
  
keep keep keep add keep keep keep keep keep
 OpenAPI: Map renderers/parsers for request/response media-types. (#6865) 
rest_framework/schemas/openapi.py