How to use a character map in XSLT?

I have this XSLT stylesheet:

<xsl:stylesheet version="3.0"
                xmlns:xsl="http://ift.tt/tCZ8VR">
    <xsl:character-map name="cm">
       <xsl:output-character character="1" string="abc"/>   
       <xsl:output-character character="2" string="def"/>
       <xsl:output-character character="3" string='ghi'/>
    </xsl:character-map>
    <xsl:template match="/">
        123abc
       <abc att="123abc"/>
       <xsl:value-of select="'123abc'"/>
    </xsl:template>
</xsl:stylesheet>

No matter how I tried, the character map did not seem to work. Could someone show me how to make it work? Did I miss something?