def is_safe_for_update(block_device_dict):
 fields = set(block_device_dict.keys())
 return (fields <= ((bdm_new_fields | bdm_db_inherited_fields) | bdm_db_only_fields))

def is_safe_for_update ( block_device_dict ) : fields = set ( block_device_dict . keys ( ) ) return ( fields <= ( ( bdm_new_fields | bdm_db_inherited_fields ) | bdm_db_only_fields ) )
determine if passed dict is a safe subset for update .