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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def values(self):
 """ Returns an `np.array` of type `dtype` containing some values from the domain. For domains where `is_finite` is ``True``, all elements of the domain will be yielded exactly once. :rtype: `np.ndarray` """

        separate_values = [domain.values for domain in self._domains]
        return np.concatenate([
            join_struct_arrays(list(map(np.array, value))) 
            for value in product(*separate_values)
        ])