FilterCondition.isNull constructor
      const
      FilterCondition.isNull({ 
    
- required String property,
Filters the results to only include objects where the property is null.
Implementation
const FilterCondition.isNull({required this.property})
    : type = FilterConditionType.isNull,
      value1 = null,
      include1 = false,
      value2 = null,
      include2 = false,
      caseSensitive = false,
      epsilon = Query.epsilon,
      super._();