def generate_annotation_dict(annotation_file):
    """ Creates a dictionary where the key is a file name
        and the value is a list containing the
            - start time
            - end time
            - bird class.
        for each annotation in that file.
    """

    annotation_dict = dict()
    for line in open(annotation_file):
        file_name, start_time, end_time, bird_class = line.strip().split('\t')

        if file_name not in annotation_dict:
            annotation_dict[file_name] = list()

        annotation_dict[file_name].append([start_time, end_time, bird_class])

    return annotation_dict