input: [==] NAN [true] true [false] false [1] false [0] false [-1] false [„1“] false [„0“] false [„-1″] false [array()] false [array(1)] false [array(„php“)] false [„php“] false [„“] false [NAN] false [null] 
output: false
options: f a l s e
options: t r u e