diff --git a/bob/bio/base/pipelines/vanilla_biometrics/legacy.py b/bob/bio/base/pipelines/vanilla_biometrics/legacy.py
index 4ce85e621a1bef6fa5deda7bfaabd651263447ab..3dd74ec709e29b76cb3f1fae28bd4b6addf09a2b 100644
--- a/bob/bio/base/pipelines/vanilla_biometrics/legacy.py
+++ b/bob/bio/base/pipelines/vanilla_biometrics/legacy.py
@@ -168,7 +168,7 @@ class BioAlgorithmLegacy(BioAlgorithm):
 
     Parameters
     ----------
-      instance: ``collection.callable``
+      instance: object
          Callable function that instantiates the :any:`bob.bio.base.algorithm.Algorithm`
 
 
diff --git a/bob/bio/base/transformers/algorithm.py b/bob/bio/base/transformers/algorithm.py
index e046842f437dcefd0b02b5f1a9d9466de95e39ae..b60adf4aac9baff83f9836d75fea8a53d9e4464b 100644
--- a/bob/bio/base/transformers/algorithm.py
+++ b/bob/bio/base/transformers/algorithm.py
@@ -26,7 +26,7 @@ class AlgorithmTransformer(TransformerMixin, BaseEstimator):
 
     Parameters
     ----------
-      instance: ``collections.callable``
+      instance: object
          Callable function that instantiates the bob.bio.base.algorithm.Algorithm
 
     """
diff --git a/bob/bio/base/transformers/extractor.py b/bob/bio/base/transformers/extractor.py
index 303859543fc8cadaaa735169c964941e2ccc3c82..bad554c2834c8e8cb149a57b8fa9eacd1e8e1bae 100644
--- a/bob/bio/base/transformers/extractor.py
+++ b/bob/bio/base/transformers/extractor.py
@@ -13,7 +13,7 @@ class ExtractorTransformer(TransformerMixin, BaseEstimator):
     Parameters
     ----------
 
-      instance: ``collections.callable``
+      instance: object
          Instance of `bob.bio.base.extractor.Extractor`
 
       model_path: ``str``