diff --git a/spinn_gym/games/breakout/breakout_machine_vertex.py b/spinn_gym/games/breakout/breakout_machine_vertex.py
index d0b2061..06ef65a 100644
--- a/spinn_gym/games/breakout/breakout_machine_vertex.py
+++ b/spinn_gym/games/breakout/breakout_machine_vertex.py
@@ -113,8 +113,8 @@ def app_vertex(self) -> 'Breakout':
     # AbstractGeneratesDataSpecification overrides
     # ------------------------------------------------------------------------
     @overrides(AbstractGeneratesDataSpecification.generate_data_specification)
-    def generate_data_specification(
-            self, spec: DataSpecificationGenerator, placement: Placement):
+    def generate_data_specification(self, spec: DataSpecificationGenerator,
+                                    placement: Placement) -> None:
         # pylint: disable=arguments-differ
         vertex = placement.vertex
 
diff --git a/spinn_gym/games/double_inverted_pendulum/double_pendulum_machine_vertex.py b/spinn_gym/games/double_inverted_pendulum/double_pendulum_machine_vertex.py
index ba3936a..16f533d 100644
--- a/spinn_gym/games/double_inverted_pendulum/double_pendulum_machine_vertex.py
+++ b/spinn_gym/games/double_inverted_pendulum/double_pendulum_machine_vertex.py
@@ -130,8 +130,8 @@ def __init__(
     # AbstractGeneratesDataSpecification overrides
     # ------------------------------------------------------------------------
     @overrides(SpinnGymMachineVertex.generate_data_specification)
-    def generate_data_specification(
-            self, spec: DataSpecificationGenerator, placement: Placement):
+    def generate_data_specification(self, spec: DataSpecificationGenerator,
+                                    placement: Placement) -> None:
         # pylint: disable=arguments-differ
         vertex = placement.vertex
 
diff --git a/spinn_gym/games/inverted_pendulum/inverted_pendulum_machine_vertex.py b/spinn_gym/games/inverted_pendulum/inverted_pendulum_machine_vertex.py
index 378ea90..8cdaceb 100644
--- a/spinn_gym/games/inverted_pendulum/inverted_pendulum_machine_vertex.py
+++ b/spinn_gym/games/inverted_pendulum/inverted_pendulum_machine_vertex.py
@@ -128,8 +128,8 @@ def __init__(self, label, app_vertex, n_neurons,
     # AbstractGeneratesDataSpecification overrides
     # ------------------------------------------------------------------------
     @overrides(AbstractGeneratesDataSpecification.generate_data_specification)
-    def generate_data_specification(
-            self, spec: DataSpecificationGenerator, placement: Placement):
+    def generate_data_specification(self, spec: DataSpecificationGenerator,
+                                    placement: Placement) -> None:
         # pylint: disable=arguments-differ
         vertex = placement.vertex
 
diff --git a/spinn_gym/games/logic/logic_machine_vertex.py b/spinn_gym/games/logic/logic_machine_vertex.py
index 80d73f6..db49f48 100644
--- a/spinn_gym/games/logic/logic_machine_vertex.py
+++ b/spinn_gym/games/logic/logic_machine_vertex.py
@@ -111,8 +111,8 @@ def __init__(self, label, app_vertex, n_neurons,
     # AbstractGeneratesDataSpecification overrides
     # ------------------------------------------------------------------------
     @overrides(AbstractGeneratesDataSpecification.generate_data_specification)
-    def generate_data_specification(
-            self, spec: DataSpecificationGenerator, placement: Placement):
+    def generate_data_specification(self, spec: DataSpecificationGenerator,
+                                    placement: Placement) -> None:
         # pylint: disable=arguments-differ
         vertex = placement.vertex
 
diff --git a/spinn_gym/games/multi_arm_bandit/bandit_machine_vertex.py b/spinn_gym/games/multi_arm_bandit/bandit_machine_vertex.py
index 676f090..272f9df 100644
--- a/spinn_gym/games/multi_arm_bandit/bandit_machine_vertex.py
+++ b/spinn_gym/games/multi_arm_bandit/bandit_machine_vertex.py
@@ -122,8 +122,8 @@ def __init__(self, label, app_vertex, n_neurons, simulation_duration_ms,
     # AbstractGeneratesDataSpecification overrides
     # ------------------------------------------------------------------------
     @overrides(AbstractGeneratesDataSpecification.generate_data_specification)
-    def generate_data_specification(
-            self, spec: DataSpecificationGenerator, placement: Placement):
+    def generate_data_specification(self, spec: DataSpecificationGenerator,
+                                    placement: Placement) -> None:
         # pylint: disable=arguments-differ
         vertex = placement.vertex
 
diff --git a/spinn_gym/games/store_recall/store_recall_machine_vertex.py b/spinn_gym/games/store_recall/store_recall_machine_vertex.py
index 1b4163c..6fdd738 100644
--- a/spinn_gym/games/store_recall/store_recall_machine_vertex.py
+++ b/spinn_gym/games/store_recall/store_recall_machine_vertex.py
@@ -117,8 +117,8 @@ def __init__(self, label,  app_vertex, n_neurons,
     # AbstractGeneratesDataSpecification overrides
     # ------------------------------------------------------------------------
     @overrides(AbstractGeneratesDataSpecification.generate_data_specification)
-    def generate_data_specification(
-            self, spec: DataSpecificationGenerator, placement: Placement):
+    def generate_data_specification(self, spec: DataSpecificationGenerator,
+                                    placement: Placement) -> None:
         # pylint: disable=arguments-differ
         vertex = placement.vertex