Error Call to undefined method App\Models\UserModel::escapeString

Mohon bantuannya kakak-kakak.

Jdi saya mau update data profile, tapi ketika saya mengakses menu update profile muncul pesan  Error Call to undefined method App\Models\UserModel::escapeString, errornya muncul ketika saya tambahakan kode berikut :

$id = $userModel->escapeString(esc($this->request->uri->getSegment(4)));

Controller :

public function change_profile()
	{

		helper(['form', 'url']);
		$userModel = new UserModel();

		$id = $userModel->escapeString(esc($this->request->uri->getSegment(4)));

		if ($this->request->getMethod() == 'post') {
			$rules = [
				'nama' 		=> 'required|alpha_space|min_length[2]',

			];

			if ($this->validate($rules)) {
				$params = [
					'nama' 		=> $userModel->escapeString(esc($this->request->getPost('nama'))),

				];

				$update = $userModel->update($id, $params);

				if ($update) {
					session()->setFlashdata('success', 'Berhasil edit data');
					return redirect()->route('admin/user/change_profile');
				} else {
					session()->setFlashdata('danger', 'Gagal edit data');
					return redirect()->route('admin/user/change_profile')->withInput();
				}
			} else {
				$data['validation'] = $this->validator;
			}
		}

		$data['title'] = 'Dokumen';
		$data['user'] = $userModel->find($id);

		return view('admin/users/profile', $data);
	}

View :

<div class="container">
		    <div class="card">
		        <div class="card-body">
    				<form action="<?= base_url('admin/user/change_profile') ?>" method="POST" enctype="multipart/form-data">
    					<?= csrf_field(); ?>

    					<div class="form-group">
				          <label for="nama">Nama</label>
				          <input type="text" class="form-control" name="nama" id="nama" value="<?= $user['nama'] ?>" >
				        </div>

						 <input type="submit" value="Update" class="btn btn-info"/>
				    </form>
    			</div>
    		</div>
    	</div>

Screenshot_1.png

Mohon bantunnya, kesalahan dari kode saya dibagian mananya ya? Terimakasih