Function normalize_unicode 

pub fn normalize_unicode<N: DomNavigator>(
    _context: &mut DynamicContext<'_, N>,
    args: Vec<XPathValue<N>>,
) -> Result<XPathValue<N>, XPathError>

fn:normalize-unicode($arg as xs:string?) as xs:string fn:normalize-unicode($arg as xs:string?, $normalizationForm as xs:string) as xs:string

Normalizes a string using Unicode normalization.