code: def test_to_csv(self):
      tableset = TableSet(self.tables.values(), self.tables.keys())
  
      tableset.to_csv(".test-tableset")
  
      for name in ["table1", "table2", "table3"]:
          with open(".test-tableset/%s.csv" % name) as f:
              contents1 = f.read()
  
          with open("examples/tableset/%s.csv" % name) as f:
              contents2 = f.read()
  
          self.assertEqual(contents1, contents2)
  
      shutil.rmtree(".test-tableset")
  
imports: import json
  import shutil
  from collections import OrderedDict
  from io import StringIO
  from agate import Table, TableSet
  from agate.computations import Formula
  from agate.data_types import Number, Text
  from agate.testcase import AgateTestCase
label_desc: Use image node_id 9 for calling the TestTableSet obj's underlying member method code with example usage: obj.test_to_csv() without return types