def processLine(line):
    """ Given a string like this: '01. anime_name---------: Naruto'
    This function returns a list: ['01. anime name', 'Naruto'] 
    which is later used as key-value pairs in our data dictionary.
    """
    sep_index = line.find('-:')
    if sep_index == -1:
            err_msg = 'Index Error. Can\'t find the index of "-:"'
            err_msg += 'in the following input line.\n"' + line + '"\n'
            raise ValueError(err_msg)

    key_end_index = -1 
    for i in range(sep_index - 1, -1, -1):  # if sep_index is 4, loop through 3, 2, 1, 0
        if line[i] != '-':
            key_end_index = i
            break

    key = line[0:key_end_index + 1]
    value = line[sep_index + 3:]    # 'key-: value' sep_index = 3, index of value, 3 + 3
    return [key, value]