isExists static method Null safety

1. baguette
2. TagUtils
3. TagUtils
4. isExists static method

TagUtils class

1. Constructors
2. TagUtils
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. Operators
10. operator ==
11. Static methods
12. isExists
13. showTags