def calculate_frequencies(tokens: list) -> dict:
    """
    Calculates frequencies of given tokens
    :param tokens: a list of tokens without stop words
    :return: a dictionary with frequencies
    e.g. tokens = ['weather', 'sunny', 'man', 'happy']
    --> {'weather': 1, 'sunny': 1, 'man': 1, 'happy': 1}
    """
    if not isinstance(tokens, list):
        return {}
    if len(tokens) > 0 and not isinstance(tokens[0], str):
        return {}
    set_words = set(tokens.copy())
    dict_freq = {word: tokens.count(word) for word in set_words}
    return dict_freq