macro_rules! expand_custom_option_vec { ($(impl Custom for Option<Vec<$fname:ident>> ($func:ident, $extract:ident, $default: expr, $to_json_array:ident))*) => { ... }; }
macro_rules! expand_custom_option_vec { ($(impl Custom for Option<Vec<$fname:ident>> ($func:ident, $extract:ident, $default: expr, $to_json_array:ident))*) => { ... }; }