/span><a href="https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-boolean/index.html">Boolean</a><span class="clearfix"><span class="floating-right">(<a href="https://github.com/buszi/Boomerang/src/androidMain/kotlin/io/buszi/boomerang/core/AndroidBoomerang.kt#L157">source</a>)</span></span></div><p class="paragraph">Checks if a value exists for the given key.</p><span class="kdoc-tag"><h4 class="">Return</h4><p class="paragraph">true if a value exists for the key, false otherwise</p></span><h4 class="">