def generate_frequency_dict(data):
    """Generate a dictionary of all symbols (keys) with their number of appearances
    (values) from data.
    """

    dict_appearances = {}

    for crrt_char in data:
        if crrt_char in dict_appearances:
            dict_appearances[crrt_char] += 1
        else:
            dict_appearances[crrt_char] = 1

    return dict_appearances