public CsvReader ignoreComments(String commentPrefix) {
        if (commentPrefix == null || commentPrefix.length() == 0) {
            throw new IllegalArgumentException(
                    "The comment prefix must not be null or an empty string");
        }

        this.commentPrefix = commentPrefix;
        return this;
    }
@Test
    void testIgnoreComments() {
        CsvReader reader = getCsvReader();
        assertThat(reader.commentPrefix).isNull();
        reader.ignoreComments("#");
        assertThat(reader.commentPrefix).isEqualTo("#");
    }