Use collection JS function from collection requests

My question:
Some of my collection requests (but not all) has to to execute the same functions (the difference is only in parameters). Iā€™d like to define js function with parameters into collection level (for example, into collection pre-request script) and use it from pre-request scripts of collection requests. I try to do it:

and use this function from collection pre-request script:

but encountered with an error:
ReferenceError: getToken is not defined

What am I doing wrong?

Details (like screenshots):
common pre-request collection function:

function getToken(email, password, tokenVariable) {
    pm.sendRequest({
        url: pm.environment.get("serviceUri") + '/api/v1/auth',
        method: 'POST',
        header: {
            'accept': 'text/plain',
            'Content-Type': 'application/json-patch+json'
        },
        body: {
            mode: 'raw',
            raw: JSON.stringify({ 'email': email, 'password': password })
        }
    }, (error, response) => {

        pm.test("Success", () => {
            pm.expect(response).to.have.property('code', 200);
        });

        pm.variables.set(tokenVariable, response.text());
    });
}

pre-request script from collection request usage:

getToken(pm.variables.get("userEmail"), pm.variables.get("userPassword"), "userToken");