input: Write a function to create an encryption and decryption application in Python. The application should take a string as input and use the AES algorithm to encrypt and decrypt the string. If the input is empty, the function should return the string "No input provided".
  assert encrypt("Hello World")==b'E\xe7\x89\xbfE\xf60\xa5\xa6~\xd1\x19/(ne'
  assert decrypt(b'E\xe7\x89\xbfE\xf60\xa5\xa6~\xd1\x19/(ne')=="Hello World"
  assert encrypt("")=="No input provided"
  assert decrypt("")=="No input provided"
output: from Crypto.Cipher import AES
  import os
  
  def encrypt(text):
      if not text:
          return "No input provided"
      key = os.urandom(16)
      cipher = AES.new(key, AES.MODE_EAX)
      nonce = cipher.nonce
      ciphertext, tag = cipher.encrypt_and_digest(text.encode())
      return ciphertext
  
  def decrypt(ciphertext):
      if not ciphertext:
          return "No input provided"
      key = os.urandom(16)
      cipher = AES.new(key, AES.MODE_EAX, nonce=nonce)
      plaintext = cipher.decrypt(ciphertext)
      return plaintext.decode()