def from_regular_arrays(self, arrays):
        """
        Merges a list of arrays (of the same shape) of dtypes 
        corresponding to the factor domains into a single array 
        with the dtype of the ``ProductDomain``.

        :param list array: A list with each element of type ``np.ndarray``

        :rtype: `np.ndarray`
        """
        return self._mytype(join_struct_arrays([
            array.astype(dtype)
            for dtype, array in zip(self._dtypes, arrays)
        ]))
Merges a list of arrays (of the same shape) of dtypes 
        corresponding to the factor domains into a single array 
        with the dtype of the ``ProductDomain``.

        :param list array: A list with each element of type ``np.ndarray``

        :rtype: `np.ndarray`