'Expand the args as a section.parameter from the config.'

def ExpandArg(self, **_):

    if (len(self.stack) <= 1):
        raise lexer.ParseError(("Unbalanced    parenthesis:    Can    not    expand    '%s'" % self.processed_buffer))
    parameter_name = self.stack.pop((-1))
    if ('.' not in parameter_name):
        parameter_name = ('%s.%s' % (self.default_section, parameter_name))
    final_value = self.config.Get(parameter_name, context=self.context)
    if (final_value is None):
        final_value = ''
    type_info_obj = (self.config.FindTypeInfo(parameter_name) or type_info.String())
    self.stack[(-1)] += type_info_obj.ToString(final_value)
