input: Write a python function to list the contents of a directory.
  assert list_directory_contents("test_directory") == ['file1.txt', 'file2.txt', 'subdirectory']
  assert list_directory_contents("empty_directory") == []
  assert list_directory_contents("another_directory") == ['another_file.docx', 'another_subdirectory']
output: def list_directory_contents(directory):
      import os
      return os.listdir(directory)