diff --git a/DESCRIPTION b/DESCRIPTION
index 265332e..36f8d5f 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -22,7 +22,7 @@ Description: Collection of tools for assessment of feature importance and featur
 Depends: R (>= 3.5)
 License: GPL-3
 Encoding: UTF-8
-RoxygenNote: 7.1.1
+RoxygenNote: 7.2.3
 Imports:
     ggplot2,
     scales,
diff --git a/NAMESPACE b/NAMESPACE
index 1728cb0..1f62c5e 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -56,6 +56,7 @@ export(show_rugs)
 import(ggplot2)
 importFrom(graphics,plot)
 importFrom(methods,hasArg)
+importFrom(methods,is)
 importFrom(scales,trans_new)
 importFrom(stats,aggregate)
 importFrom(stats,as.dist)
diff --git a/NEWS.md b/NEWS.md
index 1abf80f..2ec09e9 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -3,6 +3,8 @@ ingredients 2.3.0
 * breaking change: `calculate_variable_splits()` now treats `integer` variables as `categorical`. This change is propagated to `ceteris_paribus()`, `partial_dependence()`, `accumulated_dependence()`, `conditional_dependence()`, `aggregate_profiles()`, `DALEX::predict_profile()`, `DALEX::model_profile()`
 * fix an error in `ceteris_paribus` / `calculate_variable_splits` when `tidymodels` uses `integer` variables [#145](https://github.com/ModelOriented/ingredients/issues/145)
 * fix an error in `show_observations` [#148](https://github.com/ModelOriented/ingredients/issues/148). This change is propagated to `DALEX::plot.predict_profile()` [#540](https://github.com/ModelOriented/DALEX/issues/540).
+* fix [#149](https://github.com/ModelOriented/ingredients/issues/149) by replacing all `class(x) = "y"` with `is(x, "y")`
+
 
 ingredients 2.2.1
 --------------------------------------------------------------
diff --git a/R/describe_feature_importance.R b/R/describe_feature_importance.R
index 7d3c819..9d68aae 100644
--- a/R/describe_feature_importance.R
+++ b/R/describe_feature_importance.R
@@ -6,6 +6,7 @@
 #'
 #' @importFrom graphics plot
 #' @importFrom stats quantile
+#' @importFrom methods is
 #'
 #' @references Explanatory Model Analysis. Explore, Explain, and Examine Predictive Models. \url{https://ema.drwhy.ai/}
 #'