<s> from __future__ import absolute_import , division , print_function <EOL> import abc <EOL> import six <EOL> @ six . add_metaclass ( abc . ABCMeta ) <EOL> class AsymmetricSignatureContext ( object ) : <EOL> @ abc . abstractmethod <EOL> def update ( self , data ) : <EOL> """<STR_LIT>""" <EOL> @ abc . abstractmethod <EOL> def finalize ( self ) : <EOL> """<STR_LIT>""" <EOL> @ six . add_metaclass ( abc . ABCMeta ) <EOL> class AsymmetricVerificationContext ( object ) : <EOL> @ abc . abstractmethod <EOL> def update ( self , data ) : <EOL> """<STR_LIT>""" <EOL> @ abc . abstractmethod <EOL> def verify ( self ) : <EOL> """<STR_LIT>""" </s>
