Ds\Map::hasValue() function can determine whether the map contain a given value.
public bool Ds\Map::hasValue( mixed $value )
Ds\Map::hasValue() function can return true if the value found, or false otherwise.
<?php $map = new \Ds\Map(["1" => 10, "2" => 20, "3" => 30]); var_dump($map->hasValue(30)); ?>
<?php $map = new \Ds\Map(["1" => "Tutorials", "2" => "Point", "3" => "India"]); var_dump($map->hasValue("Point")); ?>