input: from typing import List
  
  def list_directory_contents(directory_path: str) -> List[str]:
      """ Lists the contents of a given directory.
      >>> list_directory_contents('.')
      ['file1.txt', 'subdir', 'file2.py']
      >>> list_directory_contents('nonexistent_directory')  # Raises FileNotFoundError
      """
      import os
      directory_contents = os.listdir(directory_path)
      return directory_contents
output:     import os
      if not os.path.isdir(directory_path):
          raise FileNotFoundError(f"Directory not found: {directory_path}")
      directory_contents = os.listdir(directory_path)
      return directory_contents