def sweep(freq_start=1, freq_stop=12, step=1):
    """
    Returns list of frequencies with specified parameters.
    :param freq_start:
    :param freq_stop:
    :param step:
    :return:
    """
    freqs = []
    while freq_start <= freq_stop:
        freqs.append(freq_start)
        freq_start = round(freq_start + round(step, 1), 1)
    return freqs