You’re facing this error because you’re trying to call a numpy.ndarray object as if it were a function. In Python, an object is “callable” if it behaves like a function, meaning that you can use the parenthesis, “()”, after it as if you were calling a function.

For instance, let’s say you initially set `a = numpy.array([1, 2, 3])` and then somewhere down the line you use `a()`; this would throw the error you’re seeing because `a` is an instance of ndarray, not a function or callable-type object.

Most commonly, this kind of error happens because of some confusion or oversight – you may mistakenly think you’re calling a function, when you’re really referencing an ndarray object. Just go through your code and make sure you’re calling your functions and objects correctly.

Remember, in case of numpy.ndarray, you manipulate these objects using its methods or using numpy functions, but you don’t call ndarray object itself.