add get_default_attribute method that searches both simple_attributes and defaults
add get_default_attribute method that searches both simple_attributes and defaults

opencord/xos,zdw/xos,cboling/xos,opencord/xos,zdw/xos,cboling/xos,open-cloud/xos,opencord/xos,cboling/xos,cboling/xos,cboling/xos,zdw/xos,open-cloud/xos,zdw/xos,open-cloud/xos