diff --git a/Project.toml b/Project.toml
index 9b777bc3..50286b3c 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "MarkovKernels"
 uuid = "202a2b00-fae3-41a1-a054-d2db40c1e3ea"
 authors = ["Filip Tronarp <filip.tronarp@uni-tuebingen.de> and contributors"]
-version = "0.2.0"
+version = "0.2.1"
 
 [deps]
 ArrayInterface = "4fba245c-0d91-5ea0-9b3e-6abc04ee57a9"
diff --git a/src/likelihoods.jl b/src/likelihoods.jl
index 6cc275ae..001af4ce 100644
--- a/src/likelihoods.jl
+++ b/src/likelihoods.jl
@@ -3,7 +3,7 @@
 
 Type for representing flat likelihoods.
 """
-struct FlatLikelihood end
+struct FlatLikelihood <: AbstractLikelihood end
 
 """
     Likelihood{U,V}
@@ -40,7 +40,7 @@ measurement(L::Likelihood) = L.y
 """
     log(L::Likelihood, x)
 
-Computes the logarithm of the likelihood L at x. 
+Computes the logarithm of the likelihood L at x.
 """
 log(L::Likelihood, x) = logpdf(condition(measurement_model(L), x), measurement(L))