@property<EOL><INDENT>def installed_add_ons(self):<DEDENT>
if self._installed_add_ons is None:<EOL><INDENT>self._installed_add_ons = InstalledAddOnList(self)<EOL><DEDENT>return self._installed_add_ons<EOL>
:rtype: twilio.rest.preview.marketplace.installed_add_on.InstalledAddOnList