def cdf(self, x_data):
        """
        Cumulative distribution function.

        Note that chaospy only supports cumulative distribution functions for
        stochastically independent distributions.

        Args:
            x_data (numpy.ndarray):
                Location for the distribution function. Assumes that
                ``len(x_data) == len(distribution)``.

        Returns:
            (numpy.ndarray):
                Evaluated distribution function values, where output has shape
                ``x_data.shape`` in one dimension and ``x_data.shape[1:]`` in
                higher dimensions.
        """
        if len(self) > 1 and evaluation.get_dependencies(*self):
            raise StochasticallyDependentError(
                "Cumulative distribution does not support dependencies.")
        q_data = self.fwd(x_data)
        if len(self) > 1:
            q_data = numpy.prod(q_data, 0)
        return q_data