colorSamplers class shows undefined.

Why colorSampler class shows undefined? I am trying to get RGB color values from a specific pixel of the layer. I found many solutions and most of them are using color sampler. For an example, in one of the solutions I found this >>>

var theSampler = app.activeDocument.colorSamplers.add([0.5,0.5]);

But, colorSampler class shows undefined in my case.
>> app.activeDocument.colorSamplers
undefined
>>app.activeDocument.colorSamplers.length;
(index):1 Uncaught TypeError: Cannot read properties of undefined (reading 'length')
at <anonymous>:1:34