<s> from abc import ABCMeta <EOL> from abc import abstractmethod <EOL> import six <EOL> @ six . add_metaclass ( ABCMeta ) <EOL> class ModelBase ( object ) : <EOL> def __init__ ( self , instructions ) : <EOL> self . _instructions = instructions <EOL> @ abstractmethod <EOL> def to_json ( self ) : <EOL> pass <EOL> def stringify ( self , num_spaces , index , value ) : <EOL> return '<STR_LIT>' % ( '<STR_LIT:U+0020>' * num_spaces , index , value ) </s>
