code: function MutationSigner(privateKey) {
      this.publicKey = ByteBuffer.wrap(privateKey.publicKey.toBuffer());
      this._signer = bitcore.crypto.ECDSA().set({
          endian: "big",
          privkey: privateKey.privateKey
      });
  }
docs: Provides the ability to sign a mutation.
  
  @constructor
  @param {!HDPrivateKey} privateKey The private key used to sign the mutations.