Function docker_pose::unwrap_filter_regex

pub fn unwrap_filter_regex(filter: Option<&str>) -> Option<(Regex, bool)>

Get the regex value expressed in &str, or exit if the filter passed doesn’t star with “regex=” or “regex!=” prefixes. When expression has “=” the bool is true, when is “!=” the bool is false. If the option passed is None, this method returns None as well.