'Create a GCE instance.
:param unicode instance: The name of the instance to create.
:param unicode image: The link to the GCE image to use for the base
disk. Defaults to the latest CentOS 7 image if unspecified.
:param **kwargs: Other keyword arguments for the creation of the
instance. See documentation of ``_create_gce_instance_config`` for
keyword argument values.
:returns GCEInstance: The instance that was started.'

def create_instance(self, instance_name, image=None, **kwargs):

    operation = self._execute_create_instance(instance_name, image=image, **kwargs)
    operation_result = wait_for_operation(self.compute, operation, timeout_steps=([5] * 60))
    if (not operation_result):
        raise ValueError('Timed    out    waiting    for    creation    of    VM:    {}'.format(instance_name))
    return self._make_gce_instance(instance_name)
