#NEWLINE# def _verify_subclasses( seq , required_superclass , arg_name ) : #NEWLINE# #INDENT# if ( not isinstance ( seq , collections . Sequence ) ) : #NEWLINE# #INDENT# raise errors . WrongArgTypeError ( arg_name , 'sequence (of subclasses of {0})' . format ( required_superclass . __name__ ) , type ( seq ) . __name__ ) #NEWLINE# #UNINDENT# for ( idx , elt ) in enumerate ( seq ) : #NEWLINE# #INDENT# if ( not isinstance ( elt , required_superclass ) ) : #NEWLINE# #INDENT# raise errors . WrongArgElementTypeError ( arg_name , idx , 'subclass of {0}' . format ( required_superclass . __name__ ) , type ( elt ) . __name__ )