Function interp_set_method 

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

Register an S4 method.

Stores the method in the per-interpreter S4 method dispatch table, keyed by (generic_name, signature). Falls back to binding the method under the generic name if no dispatch table entry can be created.

@param f character string naming the generic @param signature character vector or string specifying the method signature @param def function implementing the method @return the function name (invisibly)