Given a list of AlleleRead objects, extracts all unique
    (prefix, allele, suffix) sequences and associate each with the number
    of reads that contain that sequence.

def count_unique_sequences(
        allele_reads,
        max_prefix_size=None,
        max_suffix_size=None):
    """
    Given a list of AlleleRead objects, extracts all unique
    (prefix, allele, suffix) sequences and associate each with the number
    of reads that contain that sequence.
    """
    groups = group_unique_sequences(
        allele_reads,
        max_prefix_size=max_prefix_size,
        max_suffix_size=max_suffix_size)
    return {
        seq_tuple: len(read_names)
        for (seq_tuple, read_names) in groups.items()
    }