code: def test_values_sorted(self):
      rows = ((2, 2, "a"), (None, 3, "b"), (1, 4, "c"))
  
      table = Table(rows, self.column_names, self.column_types)
  
      self.assertSequenceEqual(
          table.columns["one"].values_sorted(),
          [Decimal("1"), Decimal("2"), None],
      )
  
imports: import pickle
  import unittest
  from decimal import Decimal
  from agate import Table
  from agate.data_types import Number, Text
label_desc: Use image node_id 13 for calling the TestColumn obj's underlying member method code with example usage: obj.test_values_sorted() without return types