Function interp_next_method 

fn interp_next_method(
    positional: &[RValue],
    named: &[(String, RValue)],
    context: &BuiltinContext<'_>,
) -> Result<RValue, RError>

Invoke the next method in an S3 method dispatch chain.

@param generic character string naming the generic (optional, inferred from context) @param object the object being dispatched on (optional, inferred from context) @return the result of calling the next method