Return the declarator as a single line.

def inline(self):
        """Return the declarator as a single line."""
        tp_lines, tp_decl = self.get_decl_pair()
        tp_lines = " ".join(tp_lines)
        if tp_decl is None:
            return tp_lines
        else:
            return "%s %s" % (tp_lines, tp_decl)