Function pseudo_selector_from_str 

pub fn pseudo_selector_from_str<'a>(
    selector: &'a str,
    value: Option<&'a str>,
) -> Result<CssPathPseudoSelector, CssPseudoSelectorParseError<'a>>

“selector” contains the actual selector such as “nth-child” while “value” contains an optional value - for example “nth-child(3)” would be: selector: “nth-child”, value: “3”.

Errors

Returns an error if selector (with optional value) is not a recognized CSS pseudo-selector.