diff --git a/src/abstract/hash-to-curve.ts b/src/abstract/hash-to-curve.ts
index 3bebb95..ce27c5d 100644
--- a/src/abstract/hash-to-curve.ts
+++ b/src/abstract/hash-to-curve.ts
@@ -2,7 +2,7 @@
 import type { Group, GroupConstructor, AffinePoint } from './curve.js';
 import { mod, IField } from './modular.js';
 import type { CHash } from './utils.js';
-import { bytesToNumberBE, isBytes, concatBytes, utf8ToBytes, validateObject } from './utils.js';
+import { bytesToNumberBE, abytes, isBytes, concatBytes, utf8ToBytes, validateObject } from './utils.js';
 
 /**
  * * `DST` is a domain separation tag, defined in section 2.2.5
@@ -52,10 +52,8 @@ function strxor(a: Uint8Array, b: Uint8Array): Uint8Array {
   return arr;
 }
 
-function abytes(item: unknown): void {
-  if (!isBytes(item)) throw new Error('Uint8Array expected');
-}
-function isNum(item: unknown): void {
+
+function anum(item: unknown): void {
   if (!Number.isSafeInteger(item)) throw new Error('number expected');
 }
 
@@ -69,7 +67,7 @@ export function expand_message_xmd(
 ): Uint8Array {
   abytes(msg);
   abytes(DST);
-  isNum(lenInBytes);
+  anum(lenInBytes);
   // https://www.rfc-editor.org/rfc/rfc9380#section-5.3.3
   if (DST.length > 255) DST = H(concatBytes(utf8ToBytes('H2C-OVERSIZE-DST-'), DST));
   const { outputLen: b_in_bytes, blockLen: r_in_bytes } = H;
@@ -103,7 +101,7 @@ export function expand_message_xof(
 ): Uint8Array {
   abytes(msg);
   abytes(DST);
-  isNum(lenInBytes);
+  anum(lenInBytes);
   // https://www.rfc-editor.org/rfc/rfc9380#section-5.3.3
   // DST = H('H2C-OVERSIZE-DST-' || a_very_long_DST, Math.ceil((lenInBytes * k) / 8));
   if (DST.length > 255) {
@@ -141,7 +139,7 @@ export function hash_to_field(msg: Uint8Array, count: number, options: Opts): bi
   });
   const { p, k, m, hash, expand, DST: _DST } = options;
   abytes(msg);
-  isNum(count);
+  anum(count);
   const DST = validateDST(_DST);
   const log2p = p.toString(2).length;
   const L = Math.ceil((log2p + k) / 8); // section 5.1 of ietf draft link above
diff --git a/src/abstract/utils.ts b/src/abstract/utils.ts
index 62a3fd0..186040f 100644
--- a/src/abstract/utils.ts
+++ b/src/abstract/utils.ts
@@ -23,6 +23,10 @@ export function isBytes(a: unknown): a is Uint8Array {
   );
 }
 
+export function abytes(item: unknown): void {
+  if (!isBytes(item)) throw new Error('Uint8Array expected');
+}
+
 // Array where index 0xf0 (240) is mapped to string 'f0'
 const hexes = /* @__PURE__ */ Array.from({ length: 256 }, (_, i) =>
   i.toString(16).padStart(2, '0')
@@ -31,7 +35,7 @@ const hexes = /* @__PURE__ */ Array.from({ length: 256 }, (_, i) =>
  * @example bytesToHex(Uint8Array.from([0xca, 0xfe, 0x01, 0x23])) // 'cafe0123'
  */
 export function bytesToHex(bytes: Uint8Array): string {
-  if (!isBytes(bytes)) throw new Error('Uint8Array expected');
+  abytes(bytes);
   // pre-caching improves the speed 6x
   let hex = '';
   for (let i = 0; i < bytes.length; i++) {
@@ -86,7 +90,7 @@ export function bytesToNumberBE(bytes: Uint8Array): bigint {
   return hexToNumber(bytesToHex(bytes));
 }
 export function bytesToNumberLE(bytes: Uint8Array): bigint {
-  if (!isBytes(bytes)) throw new Error('Uint8Array expected');
+  abytes(bytes);
   return hexToNumber(bytesToHex(Uint8Array.from(bytes).reverse()));
 }
 
@@ -138,7 +142,7 @@ export function concatBytes(...arrays: Uint8Array[]): Uint8Array {
   let sum = 0;
   for (let i = 0; i < arrays.length; i++) {
     const a = arrays[i];
-    if (!isBytes(a)) throw new Error('Uint8Array expected');
+    abytes(a);
     sum += a.length;
   }
   const res = new Uint8Array(sum);
@@ -194,7 +198,7 @@ export function bitGet(n: bigint, pos: number) {
 /**
  * Sets single bit at position.
  */
-export const bitSet = (n: bigint, pos: number, value: boolean) => {
+export function bitSet(n: bigint, pos: number, value: boolean) {
   return n | ((value ? _1n : _0n) << BigInt(pos));
 };