This is my data structure
 var student = {
  name: 'Tom',
  address: {
    pincode: 43301,
    street: '12th Main',
    city: 'Some city',
  },
  marks: {
    sub1: 111,
    sub2: 222
  }
}

updatProperty(student, 'marks.sub1', 125) {
  // this method should return student object with marks.sub1 to be 125
}