def infer_newX(self, Y_new, optimize=True):
from ..inference.latent_function_inference.inferenceX import infer_newX<EOL>return infer_newX(self, Y_new, optimize=optimize)<EOL>
Infer X for the new observed data *Y_new*.

:param Y_new: the new observed data for inference
:type Y_new: numpy.ndarray
:param optimize: whether to optimize the location of new X (True by default)
:type optimize: boolean
:return: a tuple containing the posterior estimation of X and the model that optimize X
:rtype: (:class:`~GPy.core.parameterization.variational.VariationalPosterior` and numpy.ndarray, :class:`~GPy.core.model.Model`)