'Returns a list of lazy-loadable expected attributes used by show
This should be used when getting the instances from the database so
that the necessary attributes are pre-loaded before needing to build
the show response where lazy-loading can fail if an instance was
deleted.
:param list expected_attrs: The list of expected attributes that will
be requested in addition to what this view builder requires. This
method will merge the two lists and return what should be
ultimately used when getting an instance from the database.
:returns: merged and sorted list of expected attributes'

def get_show_expected_attrs(self, expected_attrs=None):

    if (expected_attrs is None):
        expected_attrs = []
    return sorted(list(set((self._show_expected_attrs + expected_attrs))))
