def create_sequence_string(cluster):
    """
    Creates a string containing the cluster's sequences with their
    respective spectrum counts.

    :param cluster: The cluster to process
    :return: A string containing the cluster's sequences with their counts.
    """
    sequence_strings = list()

    if cluster.identified_spectra == 0:
        return "[]"

    for sequence in cluster.sequence_counts.keys():
        sequence_strings.append(sequence + ":" + str(cluster.sequence_counts.get(sequence)))

    final_string = "[" + ",".join(sequence_strings) + "]"

    return final_string