message: Use ==/!= to compare constant literals (str, bytes, int, float, tuple)
  Avoid `SyntaxWarning` on Python >= 3.8
  ```
  >>> "convolutional" == "convolutional"
  True
  >>> "convolutional" is "convolutional"
  <stdin>:1: SyntaxWarning: "is" with a literal. Did you mean "=="?
  True
  ```
  Related to
diff: @@ -270,12 +270,12 @@ def createSSDGraph(modelPath, configPath, outputPath):
  addConstNode('concat/axis_flatten', [-1], graph_def)
  addConstNode('PriorBox/concat/axis', [-2], graph_def)
  - for label in ['ClassPredictor', 'BoxEncodingPredictor' if box_predictor is 'convolutional' else 'BoxPredictor']:
  + for label in ['ClassPredictor', 'BoxEncodingPredictor' if box_predictor == 'convolutional' else 'BoxPredictor']:
  concatInputs = []
  for i in range(num_layers):
  # Flatten predictions
  flatten = NodeDef()
  - if box_predictor is 'convolutional':
  + if box_predictor == 'convolutional':
  inpName = 'BoxPredictor_%d/%s/BiasAdd' % (i, label)
  else:
  if i == 0:
  @@ -308,7 +308,7 @@ def createSSDGraph(modelPath, configPath, outputPath):
  priorBox = NodeDef()
  priorBox.name = 'PriorBox_%d' % i
  priorBox.op = 'PriorBox'
  - if box_predictor is 'convolutional':
  + if box_predictor == 'convolutional':
  priorBox.input.append('BoxPredictor_%d/BoxEncodingPredictor/BiasAdd' % i)
  else:
  if i == 0:
  