def clear_text(text):
    """Clean given text
    Return text with non-alphanumeric characters removed. Register ignored
    """
    alphabet = set("ʼ'’йцукенгшўзхфываёпролджэячсмітьбюqwertyuiopasdfghjklzxcvbnm0123456789XVI")
    letters = (letter for letter in text if letter.lower() in alphabet)
    return ''.join(letters)