def get_shortname(self):
disqus_shortname = self.state.document.settings.env.config.disqus_shortname<EOL>if not disqus_shortname:<EOL><INDENT>raise ExtensionError('<STR_LIT>')<EOL><DEDENT>if not RE_SHORTNAME.match(disqus_shortname):<EOL><INDENT>raise ExtensionError('<STR_LIT>')<EOL><DEDENT>return disqus_shortname<EOL>
Validate and returns disqus_shortname config value.

        :returns: disqus_shortname config value.
        :rtype: str