diff --git a/claasp/cipher_modules/models/milp/milp_models/milp_xor_differential_model.py b/claasp/cipher_modules/models/milp/milp_models/milp_xor_differential_model.py
index cdaf3e7b..862c801c 100644
--- a/claasp/cipher_modules/models/milp/milp_models/milp_xor_differential_model.py
+++ b/claasp/cipher_modules/models/milp/milp_models/milp_xor_differential_model.py
@@ -496,7 +496,7 @@ def find_one_xor_differential_trail(self, fixed_values=[], solver_name=SOLVER_DE
         EXAMPLES::
 
             # single-key setting
-            from claasp.ciphers.block_ciphers.speck_block_cipher import SpeckBlockCipher
+            sage: from claasp.ciphers.block_ciphers.speck_block_cipher import SpeckBlockCipher
             sage: from claasp.cipher_modules.models.milp.milp_models.milp_xor_differential_model import MilpXorDifferentialModel
             sage: speck = SpeckBlockCipher(number_of_rounds=5)
             sage: milp = MilpXorDifferentialModel(speck)
diff --git a/docker/Dockerfile b/docker/Dockerfile
index b35ad1bd..0658479a 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -303,6 +303,8 @@ RUN sage -pip install plotly -U kaleido
 COPY required_dependencies/sage_numerical_backends_gurobi-9.3.1.tar.gz /opt/
 RUN cd /opt/ && sage -pip install sage_numerical_backends_gurobi-9.3.1.tar.gz
 
+RUN apt-get install -y coinor-cbc coinor-libcbc-dev
+RUN sage -python -m pip install sage-numerical-backends-coin==9.0b12
 
 WORKDIR /home/sage/tii-claasp