diff --git a/ethosu/vela/npu_serialisation.py b/ethosu/vela/npu_serialisation.py
index 4542c25..29ede84 100644
--- a/ethosu/vela/npu_serialisation.py
+++ b/ethosu/vela/npu_serialisation.py
@@ -18,13 +18,15 @@
 # Description:
 # Serialises and packs an NPU subgraph into tensors.
 
+import struct
+
+import numpy as np
+
+from . import driver_actions
 from .nn_graph import PassPlacement
 from .tensor import MemArea, Tensor, TensorPurpose, TensorFormat
 from .operation import Operation
 from .data_type import DataType
-import numpy as np
-from . import driver_actions
-import struct
 
 
 def make_memory_tensor(name, mem_area, sz, want_values, arch):
@@ -75,7 +77,7 @@
     nng.total_size[scratch_area] = nng.total_size.get(scratch_area, 0) - scratch_size
     nng.total_elements[scratch_area] = nng.total_elements.get(scratch_area, 0) - scratch_size
 
-    if flash_tens == scratch_tens == None:
+    if flash_tens == scratch_tens is None:
         # First Npu subgraph, create scratch and flash tensors
         sg.scratch_tensor = make_memory_tensor(sg.name + "_scratch", scratch_area, scratch_size, False, arch)
         sg.scratch_tensor.purpose = TensorPurpose.Scratch
@@ -88,7 +90,7 @@
 
     for cps in sg.cascaded_passes:
         for ps in cps.passes:
-            if ps.placement == PassPlacement.Npu and ps.weight_tensor != None:
+            if ps.placement == PassPlacement.Npu and ps.weight_tensor is not None:
                 # For DMA ops, ps.weight_tensor is referring to the SRAM weight tensor and therefore the address
                 # is pointing at the destination address of where the weights should be placed in SRAM.
                 # This ensures that the Flash weight tensor is used instead and thus gets the correct address.