#NEWLINE# def evaluate( self , environment = None ) : #NEWLINE# #INDENT# 'Evaluate a marker.\n\n        Return the boolean from evaluating the given marker against the\n        environment. environment is an optional argument to override all or\n        part of the determined environment.\n\n        The environment is determined from the current Python process.\n        ' #NEWLINE# current_environment = default_environment ( ) #NEWLINE# if ( environment is not None ) : #NEWLINE# #INDENT# current_environment . update ( environment ) #NEWLINE# #UNINDENT# return _evaluate_markers ( self . _markers , self )