How to use the @taquito/utils.prefix.spsig function in @taquito/utils

import { b58cencode, b58cdecode, prefix, buf2hex } from '@taquito/utils';
import toBuffer from 'typedarray-to-buffer';
import elliptic from 'elliptic';

const pref = {
  p256: {
    pk: prefix['p2pk'],
    sk: prefix['p2sk'],
    pkh: prefix.tz3,
    sig: prefix.p2sig,
  },
  secp256k1: {
    pk: prefix['sppk'],
    sk: prefix['spsk'],
    pkh: prefix.tz2,
    sig: prefix.spsig,
  },
};

/**
 * @description Provide signing logic for elliptic curve based key (tz2, tz3)
 */
export class ECKey {
  private _key: Uint8Array;
  private _publicKey: Uint8Array;

  /**
   *
   * @param curve Curve to use with the key
   * @param key Encoded private key
   * @param encrypted Is the private key encrypted
   * @param decrypt Decrypt function