How to use the openupgradelib.openupgrade.rename_tables function in openupgradelib

def migrate(cr, version):
    """Update database from previous versions, after updating module."""
    openupgrade.rename_tables(
        cr=cr, table_spec=[("locomotive_backend", "shopinvader_backend")]
    )
    openupgrade.rename_models(
        cr=cr, model_spec=[("locomotive.backend", "shopinvader.backend")]
    )
    # remove blocking view
    cr.execute(
        """DELETE FROM ir_ui_view
        WHERE arch_db ilike '%locomotive_backend_ids%'"""

def pre_init_hook(cr):
    env = Environment(cr, SUPERUSER_ID, {})
    if not openupgrade.table_exists(env.cr, 'rma_order'):
        openupgrade.copy_columns(env.cr, column_copies)
        openupgrade.rename_columns(env.cr, column_renames)
        openupgrade.rename_tables(env.cr, _table_renames)
        assign_status(env.cr)
        set_default_values(env.cr)