input: Write a function named "Transpile" that takes four arguments: "src_dir", "dst_dir", "model_filename", and "params_filename". The function should create a CPUPlace object and an Executor object using Paddle Fluid. It should then create a Scope object and load the inference program, feed target names, and fetch targets using fluid.io.load_inference_model() with the given arguments. The function should clone the inference program and apply the inference transpiler using fluid.InferenceTranspiler(). The optimized inference program should be saved to "dst_dir" using fluid.io.save_persistables(). If "dst_dir" does not exist, it should be created using os.makedirs(). Finally, create a main function that uses argparse.ArgumentParser() to take in arguments and calls the "Transpile" function with the parsed arguments.
  
  assert Transpile('/path/to/src', '/path/to/dst', 'model', 'params') == None
  assert Transpile('', '/path/to/dst', 'model', 'params') == None
  assert Transpile('/path/to/src', '', 'model', 'params') == None
  assert Transpile('/path/to/src', '/path/to/dst', '', 'params') == None
  assert Transpile('/path/to/src', '/path/to/dst', 'model', '') == None
output: import os
  import paddle.fluid as fluid
  
  def Transpile(src_dir, dst_dir, model_filename, params_filename):
      if not os.path.exists(dst_dir):
          os.makedirs(dst_dir)
      
      place = fluid.CPUPlace()
      exe = fluid.Executor(place)
      scope = fluid.core.Scope()
      
      with fluid.scope_guard(scope):
          [inference_program, feed_target_names, fetch_targets] = fluid.io.load_inference_model(
              dirname=src_dir,
              executor=exe,
              model_filename=model_filename,
              params_filename=params_filename
          )
          
          transpiler = fluid.InferenceTranspiler()
          transpiler.transpile(inference_program, place)
          
          fluid.io.save_persistables(
              executor=exe,
              dirname=dst_dir,
              main_program=inference_program
          )