def generate_frequency_list(dict_appearances):
    """Generate the list to be used for building the Huffman tree from the
    dictionary of symbol appearances"""

    # total number of symbol appearances
    total_number_appearances = 0
    for key in dict_appearances:
        total_number_appearances += dict_appearances[key]

    frequency_list = []
    for key in dict_appearances:
        new_entry = (float(dict_appearances[key]) / total_number_appearances, key)
        frequency_list.append(new_entry)

    return frequency_list