code: func (v *Object) GetNull(keys ...string) error {
  	child, err := v.getPath(keys)
  
  	if err != nil {
  		return err
  	}
  
  	return child.Null()
  }
docs: // Gets the value at key path and attempts to typecast the value into null.
  // Returns error if the value is not json null.
  // Example:
  //		err := GetNull("address", "street")