input: def list_directory_contents():
      """ Lists all contents in the current directory.
      >>> list_directory_contents()
      [output of os.listdir() printed line by line]
      """
      import os
      directory_contents = os.listdir()
      for content in directory_contents:
          print(content)
output:     import os
      directory_contents = os.listdir()
      for content in directory_contents:
          print(content)