Indices of the advanced indexes subspaces for mixed indexing and vindex.

def _advanced_indexer_subspaces(key):
    """Indices of the advanced indexes subspaces for mixed indexing and vindex.
    """
    if not isinstance(key, tuple):
        key = (key,)
    advanced_index_positions = [i for i, k in enumerate(key)
                                if not isinstance(k, slice)]

    if (not advanced_index_positions or
            not _is_contiguous(advanced_index_positions)):
        # Nothing to reorder: dimensions on the indexing result are already
        # ordered like vindex. See NumPy's rule for "Combining advanced and
        # basic indexing":
        # https://docs.scipy.org/doc/numpy/reference/arrays.indexing.html#combining-advanced-and-basic-indexing
        return (), ()

    non_slices = [k for k in key if not isinstance(k, slice)]
    ndim = len(np.broadcast(*non_slices).shape)
    mixed_positions = advanced_index_positions[0] + np.arange(ndim)
    vindex_positions = np.arange(ndim)
    return mixed_positions, vindex_positions