input: 
  from Crypto.Cipher import AES
  
  key = b'Sixteen byte key'
  
  def encrypt_decrypt(operation: str, text: str) -> bytes:
      """ Encrypts or decrypts a given string using AES encryption in ECB mode.
      The function takes an operation ('encrypt' or 'decrypt') and the text to be
      processed. It returns the encrypted or decrypted text as bytes.
      
      >>> encrypt_decrypt('encrypt', 'Hello World 1234')
      b'\\x91\\x97\\xe4os\\x8f2#\\xf9\\x9e\\xb5\\xbert\\xebO'
      
      >>> encrypt_decrypt('decrypt', b'\\x91\\x97\\xe4os\\x8f2#\\xf9\\x9e\\xb5\\xbert\\xebO')
      b'Hello World 1234'
      """
      cipher = AES.new(key, AES.MODE_ECB)
      if operation == 'encrypt':
          return cipher.encrypt(text)
      elif operation == 'decrypt':
          return cipher.decrypt(text)
      else:
          raise ValueError("Invalid operation. Choose 'encrypt' or 'decrypt'.")
  
output:     cipher = AES.new(key, AES.MODE_ECB)
      if operation == 'encrypt':
          padded_text = text + (AES.block_size - len(text) % AES.block_size) * chr(AES.block_size - len(text) % AES.block_size)
          return cipher.encrypt(padded_text.encode())
      elif operation == 'decrypt':
          decrypted_text = cipher.decrypt(text).decode()
          return decrypted_text.rstrip(decrypted_text[-1])
      else:
          raise ValueError("Invalid operation. Choose 'encrypt' or 'decrypt'.")