Used in Dataset.__init__.

def merge_data_and_coords(data, coords, compat='broadcast_equals',
                          join='outer'):
    """Used in Dataset.__init__."""
    objs = [data, coords]
    explicit_coords = coords.keys()
    indexes = dict(extract_indexes(coords))
    return merge_core(objs, compat, join, explicit_coords=explicit_coords,
                      indexes=indexes)