diff --git a/spinn_pdp2/input_vertex.py b/spinn_pdp2/input_vertex.py
index 1503e23..008073b 100644
--- a/spinn_pdp2/input_vertex.py
+++ b/spinn_pdp2/input_vertex.py
@@ -329,8 +329,8 @@ def generate_machine_data_specification(
 
 
     @overrides(AbstractRewritesDataSpecification.regenerate_data_specification)
-    def regenerate_data_specification(
-            self, spec: DataSpecificationReloader, placement: Placement):
+    def regenerate_data_specification(self, spec: DataSpecificationReloader,
+                                      placement: Placement) -> None:
         # Reserve and write the stage configuration region
         spec.reserve_memory_region (MLPRegions.STAGE.value,
                                     self._STAGE_CONFIGURATION_BYTES)
@@ -350,7 +350,7 @@ def reload_required(self) -> bool:
 
 
     @overrides(AbstractRewritesDataSpecification.set_reload_required)
-    def set_reload_required(self, new_value: bool):
+    def set_reload_required(self, new_value: bool) -> None:
         """
             TODO: not really sure what this method is used for!
         """
diff --git a/spinn_pdp2/sum_vertex.py b/spinn_pdp2/sum_vertex.py
index 6d72b5b..03a3d64 100644
--- a/spinn_pdp2/sum_vertex.py
+++ b/spinn_pdp2/sum_vertex.py
@@ -358,8 +358,8 @@ def generate_machine_data_specification(
 
 
     @overrides(AbstractRewritesDataSpecification.regenerate_data_specification)
-    def regenerate_data_specification(
-            self, spec: DataSpecificationReloader, placement: Placement):
+    def regenerate_data_specification(self, spec: DataSpecificationReloader,
+                                      placement: Placement) -> None:
         # Reserve and write the stage configuration region
         spec.reserve_memory_region (MLPRegions.STAGE.value,
                                     self._STAGE_CONFIGURATION_BYTES)
@@ -379,7 +379,7 @@ def reload_required(self) -> bool:
 
 
     @overrides(AbstractRewritesDataSpecification.set_reload_required)
-    def set_reload_required(self, new_value: bool):
+    def set_reload_required(self, new_value: bool) -> None:
         """
             TODO: not really sure what this method is used for!
         """
diff --git a/spinn_pdp2/threshold_vertex.py b/spinn_pdp2/threshold_vertex.py
index b01c0e1..56a7788 100644
--- a/spinn_pdp2/threshold_vertex.py
+++ b/spinn_pdp2/threshold_vertex.py
@@ -540,8 +540,8 @@ def generate_machine_data_specification(
 
 
     @overrides(AbstractRewritesDataSpecification.regenerate_data_specification)
-    def regenerate_data_specification(
-            self, spec: DataSpecificationReloader, placement: Placement):
+    def regenerate_data_specification(self, spec: DataSpecificationReloader,
+                                      placement: Placement) -> None:
         # reserve and write the stage configuration region
         spec.reserve_memory_region (MLPRegions.STAGE.value,
                                     self._STAGE_CONFIGURATION_BYTES)
@@ -561,7 +561,7 @@ def reload_required(self) -> bool:
 
 
     @overrides(AbstractRewritesDataSpecification.set_reload_required)
-    def set_reload_required(self, new_value: bool):
+    def set_reload_required(self, new_value: bool) -> None:
         """
             TODO: not really sure what this method is used for!
         """
diff --git a/spinn_pdp2/weight_vertex.py b/spinn_pdp2/weight_vertex.py
index f3bb8eb..4dc4edc 100644
--- a/spinn_pdp2/weight_vertex.py
+++ b/spinn_pdp2/weight_vertex.py
@@ -392,8 +392,8 @@ def generate_machine_data_specification(
 
 
     @overrides(AbstractRewritesDataSpecification.regenerate_data_specification)
-    def regenerate_data_specification(
-            self, spec: DataSpecificationReloader, placement: Placement):
+    def regenerate_data_specification(self, spec: DataSpecificationReloader,
+                                      placement: Placement) -> None:
         # Reserve and write the stage configuration region
         spec.reserve_memory_region (MLPRegions.STAGE.value,
                                     self._STAGE_CONFIGURATION_BYTES)
@@ -413,7 +413,7 @@ def reload_required(self) -> bool:
 
 
     @overrides(AbstractRewritesDataSpecification.set_reload_required)
-    def set_reload_required(self, new_value: bool):
+    def set_reload_required(self, new_value: bool) -> None:
         """
             TODO: not really sure what this method is used for!
         """