def METHOD_NAME(sent: str, lang: str):
    """ Function for preprocessing the input texts. The function first does
    some basic tokenization. For English, it then also processes Greek letters
    such as Δ or λ (if any).
    Args:
        sent: input text.
        lang: language
    Returns: preprocessed input text.
    """
    # Basic Preprocessing and Tokenization
    if lang == constants.ENGLISH:
        sent = sent.replace('+', ' plus ')
        sent = sent.replace('=', ' equals ')
        sent = sent.replace('@', ' at ')
        sent = sent.replace('*', ' times ')
        # Greek letters processing
        for jx, tok in enumerate(sent):
            if tok in constants.EN_GREEK_TO_SPOKEN:
                sent = sent[:jx] + constants.EN_GREEK_TO_SPOKEN[tok] + sent[jx + 1 :]
    sent = convert_superscript(sent)
    sent = convert_fraction(sent)
    sent = add_space_around_dash(sent)
    return sent