diff --git a/src/graph/generation/graph_generation.cc b/src/graph/generation/graph_generation.cc
index 31df8c6dc9ec09f1cfedbb820a31e0b3366b2a19..c05a4b6649538d99d22c1d4c1c0fe3ce4be274b3 100644
--- a/src/graph/generation/graph_generation.cc
+++ b/src/graph/generation/graph_generation.cc
@@ -15,7 +15,7 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with this program. If not, see <http://www.gnu.org/licenses/>.
 
-#define BOOST_PYTHON_MAX_ARITY 40
+#define BOOST_PYTHON_MAX_ARITY 20
 
 #include "graph.hh"
 #include "graph_util.hh"
diff --git a/src/graph/inference/layers/graph_blockmodel_layers.cc b/src/graph/inference/layers/graph_blockmodel_layers.cc
index 40003e25a1616d1e4832e752f795b5da46f3903c..6fdb997a7de0c1089b4b61081a913bcf71534c7c 100644
--- a/src/graph/inference/layers/graph_blockmodel_layers.cc
+++ b/src/graph/inference/layers/graph_blockmodel_layers.cc
@@ -15,7 +15,7 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with this program. If not, see <http://www.gnu.org/licenses/>.
 
-#define BOOST_PYTHON_MAX_ARITY 40
+#define BOOST_PYTHON_MAX_ARITY 20
 #include <boost/python.hpp>
 
 #include "graph_tool.hh"
diff --git a/src/graph/inference/layers/graph_blockmodel_layers_imp.cc b/src/graph/inference/layers/graph_blockmodel_layers_imp.cc
index 1afc233aef5e1c22bf348ee70bc3df4139eccc55..57f94ef56e22d0ca7db8e0bcda2c2562377acc7d 100644
--- a/src/graph/inference/layers/graph_blockmodel_layers_imp.cc
+++ b/src/graph/inference/layers/graph_blockmodel_layers_imp.cc
@@ -15,7 +15,6 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with this program. If not, see <http://www.gnu.org/licenses/>.
 
-#define BOOST_PYTHON_MAX_ARITY 40
 #include <boost/python.hpp>
 
 #include "graph_tool.hh"
diff --git a/src/graph/inference/uncertain/graph_blockmodel_dynamics_cising_glauber.cc b/src/graph/inference/uncertain/graph_blockmodel_dynamics_cising_glauber.cc
index 9e61a672954736d0d2b0fe6ec955041ad1f7c2b5..797e8ac4d6fc9949809dc68d3f018ebe8418699e 100644
--- a/src/graph/inference/uncertain/graph_blockmodel_dynamics_cising_glauber.cc
+++ b/src/graph/inference/uncertain/graph_blockmodel_dynamics_cising_glauber.cc
@@ -15,7 +15,6 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with this program. If not, see <http://www.gnu.org/licenses/>.
 
-#define BOOST_PYTHON_MAX_ARITY 40
 #include <boost/python.hpp>
 
 #include "graph_tool.hh"
diff --git a/src/graph/inference/uncertain/graph_blockmodel_dynamics_epidemics.cc b/src/graph/inference/uncertain/graph_blockmodel_dynamics_epidemics.cc
index 861c93ba55382ede2a104fa462290377db500942..f11d7a8a67d5e1b7cfe66442563868f89929c6f2 100644
--- a/src/graph/inference/uncertain/graph_blockmodel_dynamics_epidemics.cc
+++ b/src/graph/inference/uncertain/graph_blockmodel_dynamics_epidemics.cc
@@ -15,7 +15,6 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with this program. If not, see <http://www.gnu.org/licenses/>.
 
-#define BOOST_PYTHON_MAX_ARITY 40
 #include <boost/python.hpp>
 
 #include "graph_tool.hh"
diff --git a/src/graph/inference/uncertain/graph_blockmodel_dynamics_ising_glauber.cc b/src/graph/inference/uncertain/graph_blockmodel_dynamics_ising_glauber.cc
index c1138a7cdfaefacc85a2e5f188b74866e2acfdc9..b870e0270745c4718c887cfe77ba48b4c64217eb 100644
--- a/src/graph/inference/uncertain/graph_blockmodel_dynamics_ising_glauber.cc
+++ b/src/graph/inference/uncertain/graph_blockmodel_dynamics_ising_glauber.cc
@@ -15,7 +15,6 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with this program. If not, see <http://www.gnu.org/licenses/>.
 
-#define BOOST_PYTHON_MAX_ARITY 40
 #include <boost/python.hpp>
 
 #include "graph_tool.hh"
diff --git a/src/graph/inference/uncertain/graph_blockmodel_dynamics_pseudo_cising.cc b/src/graph/inference/uncertain/graph_blockmodel_dynamics_pseudo_cising.cc
index f65b51c8239513e548300c367c5680fcf0520cfc..9feb53e4eb55b7449c9ea8cf073ef8e61621738e 100644
--- a/src/graph/inference/uncertain/graph_blockmodel_dynamics_pseudo_cising.cc
+++ b/src/graph/inference/uncertain/graph_blockmodel_dynamics_pseudo_cising.cc
@@ -15,7 +15,6 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with this program. If not, see <http://www.gnu.org/licenses/>.
 
-#define BOOST_PYTHON_MAX_ARITY 40
 #include <boost/python.hpp>
 
 #include "graph_tool.hh"
diff --git a/src/graph/inference/uncertain/graph_blockmodel_dynamics_pseudo_ising.cc b/src/graph/inference/uncertain/graph_blockmodel_dynamics_pseudo_ising.cc
index a0923d3900e647c2dce7f892fd011b66105d36fb..e7b124525e678cd6bfd8608dd0819970db37f677 100644
--- a/src/graph/inference/uncertain/graph_blockmodel_dynamics_pseudo_ising.cc
+++ b/src/graph/inference/uncertain/graph_blockmodel_dynamics_pseudo_ising.cc
@@ -15,7 +15,6 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with this program. If not, see <http://www.gnu.org/licenses/>.
 
-#define BOOST_PYTHON_MAX_ARITY 40
 #include <boost/python.hpp>
 
 #include "graph_tool.hh"
diff --git a/src/graph/inference/uncertain/graph_blockmodel_measured.cc b/src/graph/inference/uncertain/graph_blockmodel_measured.cc
index 0a20ee746faa642877954dfc5795c634b070f340..f0119d9e39bba7bde70c4450134c5d9ee61a6a8f 100644
--- a/src/graph/inference/uncertain/graph_blockmodel_measured.cc
+++ b/src/graph/inference/uncertain/graph_blockmodel_measured.cc
@@ -15,7 +15,6 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with this program. If not, see <http://www.gnu.org/licenses/>.
 
-#define BOOST_PYTHON_MAX_ARITY 40
 #include <boost/python.hpp>
 
 #include "graph_tool.hh"
diff --git a/src/graph/inference/uncertain/graph_blockmodel_uncertain.cc b/src/graph/inference/uncertain/graph_blockmodel_uncertain.cc
index d2b5ad22244600fdf0490b33313ae10c2059636e..0e779582c5594b5130f836913df2abaf2a47d231 100644
--- a/src/graph/inference/uncertain/graph_blockmodel_uncertain.cc
+++ b/src/graph/inference/uncertain/graph_blockmodel_uncertain.cc
@@ -15,7 +15,6 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with this program. If not, see <http://www.gnu.org/licenses/>.
 
-#define BOOST_PYTHON_MAX_ARITY 40
 #include <boost/python.hpp>
 
 #include "graph_tool.hh"