input: Write a python function to list the contents of a given directory.
  assert list_directory_contents(".") == os.listdir(".")
  assert list_directory_contents("/tmp") == os.listdir("/tmp")
  assert list_directory_contents("/nonexistent") == []
output: import os
  
  def list_directory_contents(directory):
      try:
          return os.listdir(directory)
      except FileNotFoundError:
          return []