<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _qname(self) -> Optional[QualName]: """Parse XML QName."""

        if self.test_string("*"):
            self.skip_ws()
            return False
        ident = self.yang_identifier()
        ws = self.skip_ws()
        try:
            next = self.peek()
        except EndOfInput:
            return ident, None
        if next == "(":
            return self._node_type(ident)
        if not ws and self.test_string(":"):
            res = (
                self.yang_identifier(),
                self.sctx.schema_data.prefix2ns(ident, self.sctx.text_mid))
        else:
            res = (ident, None)
        self.skip_ws()
        return res