Function from_hosts_expression_to_xname_vec 

pub fn from_hosts_expression_to_xname_vec(
    user_input: &str,
    is_include_siblings: bool,
    node_metadata_available_vec: &[Component],
) -> Result<Vec<String>, Error>

Translates a ‘host expression’ into a list of xnames.

A host expression is a comma-separated list of NIDs or xnames, a regex, or a hostlist. When is_include_siblings is true, the resulting xnames are expanded to include all siblings (other nodes on the same BMC).