add
Adds the specified element to the set.
Since Kotlin
1.3Return
true
if the element has been added, false
if the element is already contained in the set.
Adds the specified element to the set.
This method is redeclared as abstract, because it's not implemented in the base class, so it must be always overridden in the concrete mutable collection implementation.
Since Kotlin
1.1Return
true
if the element has been added, false
if the element is already contained in the set.