How to use sub capture and gather together

test.raku

  sub dims-match( @a ) {
      given @a {
          when *== 0 { '' }
          when *== 1 { .first }
          when *>= 2 { .&type-hint }
      }
  }

  gather {
      for $.dictionary.type-to-dims.kv -> $key, $value {
          take $key if $value eqv self.dims
      }
 } ==> dims-match