#NEWLINE# @ contextmanager #NEWLINE# def create_jar_builder( self , jar ) : #NEWLINE# #INDENT# 'Creates a ``JarTask.JarBuilder`` ready for use.\n\n    This method should be called during in `execute` context and only after ensuring\n    `JarTask.JarBuilder.prepare` has already been called in `prepare` context.\n\n    :param jar: An opened ``pants.backend.jvm.tasks.jar_task.Jar`.\n    ' #NEWLINE# builder = self . JarBuilder ( self . context , jar ) #NEWLINE# ( yield jar ) #NEWLINE# builder . commit_manifest ( jar )