How to use the pyfaidx.FetchError function in pyfaidx

    @raises(FetchError)
    def test_bounds_error(self):
        result = self.genes_buffer['KF435150.1'][100-1:15000].seq.lower()

    @raises(FetchError)
    def test_fetch_past_bounds(self):
        """ Fetch past the end of a gene entry """
        faidx = Faidx('data/genes.fasta', strict_bounds=True)
        result = faidx.fetch('gi|557361099|gb|KF435150.1|',
                                         480, 5000)

    @raises(FetchError)
    def test_fetch_error(self):
        main(['data/genes.fasta', 'gi|557361099|gb|KF435150.1|:1-1000'])

    @raises(FetchError)
    def test_fetch_border(self):
        """ Fetch past the end of a gene entry """
        faidx = Faidx('data/genes.fasta.gz')
        expect = 'TC'
        result = faidx.fetch('gi|557361099|gb|KF435150.1|',
                             480, 500)
        print(result)
        assert str(result) == expect

    @raises(FetchError)
    def test_fetch_negative(self):
        """ Fetch starting with a negative coordinate """
        faidx = Faidx('data/genes.fasta.gz', strict_bounds=True)
        result = faidx.fetch('gi|557361099|gb|KF435150.1|',
                                         -10, 10)

    @raises(FetchError)
    def test_fetch_negative(self):
        """ Fetch starting with a negative coordinate """
        faidx = Faidx('data/genes.fasta', strict_bounds=True)
        result = faidx.fetch('gi|557361099|gb|KF435150.1|',
                                         -10, 10)

outfile = open(filename, 'w')
        elif args.out:
            outfile = args.out
        else:
            outfile = sys.stdout
        try:
            if args.transform:
                if not header and args.transform == 'nucleotide':
                    outfile.write("name\tstart\tend\tA\tT\tC\tG\tN\tothers\n")
                    header = True
                outfile.write(transform_sequence(args, fasta, name, start, end))
            else:
                for line in fetch_sequence(args, fasta, name, start, end):
                    outfile.write(line)
        except FetchError as e:
            raise FetchError(str(e) + " Try setting --lazy.\n")
        if args.split_files:
            outfile.close()
    fasta.__exit__()

filename = ''.join(c for c in filename if c.isalnum() or c in keepcharacters)
            outfile = open(filename, 'w')
        elif args.out:
            outfile = args.out
        else:
            outfile = sys.stdout
        try:
            if args.transform:
                if not header and args.transform == 'nucleotide':
                    outfile.write("name\tstart\tend\tA\tT\tC\tG\tN\tothers\n")
                    header = True
                outfile.write(transform_sequence(args, fasta, name, start, end))
            else:
                for line in fetch_sequence(args, fasta, name, start, end):
                    outfile.write(line)
        except FetchError as e:
            raise FetchError(str(e) + " Try setting --lazy.\n")
        if args.split_files:
            outfile.close()
    fasta.__exit__()