code: def tearDown(self):
      if os.path.exists(self.array_file):
          os.remove(self.array_file)
      else:
          raise FileNotFoundError("array has not been stored to file")
  
imports: import os
  import unittest
  import uuid
  import gc
  from scipy import sparse
  import numpy
  from tick.array.serialize import serialize_array, load_array
label_desc: Use image node_id 3 for calling the Test obj's underlying member method code with example usage: obj.tearDown() without return types