code: def test_select(self):
      tableset = TableSet(self.tables.values(), self.tables.keys())
  
      new_tableset = tableset.select(["number"])
  
      for name, new_table in new_tableset.items():
          self.assertColumnNames(new_table, ("number",))
          self.assertColumnTypes(new_table, (Number,))
  
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 18 for calling the TestTableSet obj's underlying member method code with example usage: obj.test_select() without return types