human
Solve the following python programming problem given the following code:
@ attr ('requires_hadoop') 
def test_copy_files() : 
    cluster = pseudo_hdfs4.shared_cluster () 
    try : 
        c = make_logged_in_client () 
        user = User.objects.get (username = 'test') 
        prefix = '/tmp/test_copy_files' 
        if cluster.fs.exists (prefix) : 
            cluster.fs.rmtree (prefix) 
deployment_dir = ('%s/workspace' % prefix) 
        external_deployment_dir = ('%s/deployment' % prefix) 
        jar_1 = ('%s/udf1.jar' % prefix) 
        jar_2 = ('%s/lib/udf2.jar' % prefix) 
        jar_3 = ('%s/udf3.jar' % deployment_dir) 
        jar_4 = ('%s/lib/udf4.jar' % deployment_dir) 
        cluster.fs.mkdir (prefix) 
        cluster.fs.create (jar_1) 
        cluster.fs.create (jar_2) 
        cluster.fs.create (jar_3) 
        cluster.fs.create (jar_4) 
        class MockNode () : 
            def __init__(self, jar_path) : 
                self.jar_path = jar_path 
class MockJob () : 
            def __init__(self) : 
                self.node_list = [MockNode (jar_1), MockNode (jar_2), MockNode (jar_3), MockNode (jar_4)] 
def get_application_filename(self) : 
                return 'workflow.xml' 
submission = Submission (user, job = MockJob (), fs = cluster.fs, jt = cluster.jt) 
        submission._copy_files (deployment_dir, '<xml>My XML</xml>') 
        submission._copy_files (external_deployment_dir, '<xml>My XML</xml>') 
        assert_true (cluster.fs.exists (jar_1)) 
        assert_true (cluster.fs.exists (jar_2)) 
        assert_true (cluster.fs.exists (jar_3)) 
        assert_true (cluster.fs.exists (jar_4)) 
        deployment_dir = (deployment_dir + '/lib') 
        external_deployment_dir = (external_deployment_dir + '/lib') 
        list_dir_workspace = cluster.fs.listdir (deployment_dir) 
        list_dir_deployement = cluster.fs.listdir (external_deployment_dir) 
        assert_true (cluster.fs.exists ((deployment_dir + '/udf1.jar')), list_dir_workspace) 
        assert_true (cluster.fs.exists ((deployment_dir + '/udf2.jar')), list_dir_workspace) 
       ...

    
    

    Fix the buggy line: assert_true (cluster.fs.exists ((external_deployment_dir + '/udf3.jar')), stats_udf1)
assistant
#Here is Python code to fix the buggy line: assert_true (cluster.

assert_true (cluster.fs.exists ((external_deployment_dir + '/udf3.jar')), list_dir_deployement)