code: func (d *ResourceData) GetOkExists(key string) (interface{}, bool) {
  	r := d.getRaw(key, getSourceSet)
  	exists := r.Exists && !r.Computed
  	return r.Value, exists
  }
docs: // GetOkExists returns the data for a given key and whether or not the key
  // has been set to a non-zero value. This is only useful for determining
  // if boolean attributes have been set, if they are Optional but do not
  // have a Default value.
  //
  // This is nearly the same function as GetOk, yet it does not check
  // for the zero value of the attribute's type. This allows for attributes
  // without a default, to fully check for a literal assignment, regardless
  // of the zero-value for that type.
  // This should only be used if absolutely required/needed.