def remove_unicharacter(sent, return_str=True):
    """
    Remove the single letter from the sentence

    :param sent: str, the sentence to remove non-alphabetic
    :param return_str: bool, return str when set to True, otherwise return tokenized list. default True
    :return: str, the sentense after single characters are removed
    """
    sent = [word for word in sent.split() if len(word) > 1]

    if return_str:
        sent = " ".join(sent)

    return sent