def METHOD_NAME(seq_type):
    path = os.path.join(data_dir("sequence"), "nuc.fasta")
    file = fasta.FastaFile.read(path)
    sequences = fasta.get_sequences(file, seq_type=seq_type)
    assert sequences == {
        "dna sequence" : seq.NucleotideSequence("ACGCTACGT", False),
        "another dna sequence" : seq.NucleotideSequence("A", False),
        "third dna sequence" : seq.NucleotideSequence("ACGT", False),
        "rna sequence" : seq.NucleotideSequence("ACGT", False),
        "ambiguous rna sequence" : seq.NucleotideSequence("ACGTNN", True),
    }