public StringAppender append(final String message) {
        if(StringUtils.isBlank(StringUtils.trim(message))) {
            return this;
        }
        if(buffer.length() > 0) {
            buffer.append(" ");
        }
        buffer.append(StringUtils.trim(message));
        if(buffer.charAt(buffer.length() - 1) == '.') {
            return this;
        }
        if(buffer.charAt(buffer.length() - 1) == ':') {
            buffer.deleteCharAt(buffer.length() - 1);
        }
        if(!Pattern.matches("[.?!]", String.valueOf(buffer.charAt(buffer.length() - 1)))) {
            buffer.append(suffix);
        }
        return this;
    }
@Test
    public void testAppend() {
        assertEquals("Verification Code.", new StringAppender().append("Verification Code:").toString());
        assertEquals("Message.", new StringAppender().append("Message").toString());
        assertEquals("Message.", new StringAppender().append("Message.").toString());
        assertEquals("Message? t.", new StringAppender().append("Message?").append("t").toString());
        assertEquals("Message).", new StringAppender().append("Message)").toString());
        assertEquals("m.", new StringAppender().append("m").append(" ").toString());
    }