import curry from './curry.js';
import compose from './compose.js';
import head from './head.js';
import tail from './tail.js';
import concat from './concat.js';

// (a -> a) -> a
const transformHead = curry((f, s) => concat(compose(f, head)(s), tail(s)));

export default transformHead;

import R from 'ramda';
import curry from './curry.js';
import compose from './compose.js';
import head from './head.js';
import tail from './tail.js';

// (a -> a) -> a
const transformHead = curry((f, s) => {
  return R.concat(
    compose(f, head)(s),
    tail(s)
  );
});

export default transformHead;

--- 
+++ 
@@ -1,10 +1,15 @@
+import R from 'ramda';
 import curry from './curry.js';
 import compose from './compose.js';
 import head from './head.js';
 import tail from './tail.js';
-import concat from './concat.js';
 
 // (a -> a) -> a
-const transformHead = curry((f, s) => concat(compose(f, head)(s), tail(s)));
+const transformHead = curry((f, s) => {
+  return R.concat(
+    compose(f, head)(s),
+    tail(s)
+  );
+});
 
 export default transformHead;
Refactor the transformHead function to use the custom concat function
