import re


def clean(name):
    """Clean name by only keeping the key-words in it.

    Args:
        name (str): name we are cleaning.

    Returns:
        relevant_sentence (str): cleaned name
    """
    if str(name) != "nan":
        # seperate in words
        name_lowercase = name.lower()
        relevant_words = re.findall(r"[a-z]+", name_lowercase)

        # remove one letter words
        relevant_words = [word for word in relevant_words if len(word) > 1]

        relevant_sentence = " ".join(relevant_words)
        return relevant_sentence
    else:
        return None