def set_dtype(cls, value=DTYPE_FLOAT):
        """Set the feature's data type.

        Parameters
        ----------
        value : {DTYPE_FLOAT, DTYPE_INT, DTYPE_OBJECT}
            The data type.

        Raises
        ------
        ValueError
            If the data type is not one of the allowed types.

        """
        if value not in [np.float64, np.int32, np.object]:
            raise ValueError("Attribute 'dtype' must be one of the allowed types, got %s" % str(type(value)))
        cls.dtype = value