public function set($key, $value)
    {
        if ($this->exists($key)) {
            $this->dataStore[$key] = $value;
        }
    }
public function set($key, $value)
    {
        if ($this->exists($key)) {
            $this->dataStore[$key] = $value;
        }
    }
public function set ( $ key , $ value ) { if ( $ this -> exists ( $ key ) ) { $ this -> dataStore [ $ key ] = $ value ; } }
Set the given value to the given key.

The given key should match one of the parameters about, but with out the
prefix. That is added on during this process.

@param string $key
@param mixed $value
Set the given value to the given key .