Converts raw values into ranks for rank correlation coefficients
    :param values: list of values (int/float)
    :return: a dict mapping value -> rank

def get_ranks(values):
    '''
    Converts raw values into ranks for rank correlation coefficients
    :param values: list of values (int/float)
    :return: a dict mapping value -> rank
    '''
    ranks = {}
    sorted_values = sorted(values)
    for i in range(len(sorted_values)):
        value = sorted_values[i]
        if value not in ranks:
            ranks[value] = i + 1
    return ranks