Functions written inside the File not getting mocked in Node js Test case

I have following file which I am trying to write test cases for .

VehicleAssign.ts

expot const vehicleAssignSPO = async(gettersetter, input) => {
 //some code
 try {
    await checkExpiredSPO(getterSetter, "some value")
}
}


 export const checkExpiredSPO = async(getterSetter, flmt) => {
  
  //some code
   
  }

Now I am trying to write a test case for this file.

VehicleAssign.test.ts

  it('Should be able to call the Function Successfully', async () => {
        const input = mockInput();

         jest.mock('../helpers/vehicleAssignSPO.helper', () => ({
            checkExpiredSPO: jest.fn().mockResolvedValue({})
        }))
       
        const result = await vehicleAssignSPO(getterSetterMock, input)
    })

But here I am mocking the function checkExpiredSPO but still is calling the actual function and the mocked one.

How Can I fix this ?