Which feature is used in XML to ensure that all attributes and elements have unique names?

Which statement is correct about YAML?

As part of an application to manage network devices, you must query hundreds of network devices and return the unique set of IP prefixes by configured firewall filters. To accomplish this task you will require a mutable data type that contains unordered, unique elements.
Which Python data type will fulfill these requirements?

Which character is used to separate multiple parameters in a single REST API call?

Which two statements about DevOps are correct? (Choose two.)