code: func Filter(array []interface{}, iterator ConditionIterator) []interface{} {
  	var result = make([]interface{}, 0)
  	for index, data := range array {
  		if iterator(data, index) {
  			result = append(result, data)
  		}
  	}
  	return result
  }
docs: // Filter iterates over the slice and apply ConditionIterator to every item. Returns new slice.