text: from unittest import TestCase
  from followthemoney.util import merge_context
  
  
  class UtilTestCase(TestCase):
      def test_merge_value(self):
          old = {
              "foo": "bar",
          }
          new = {
              "foo": "quux",
          }
          result = merge_context(old, new)
          assert result["foo"] == ["bar", "quux"], result
  
      def test_merge_different(self):
          old = {
              "foo": "quux",
          }
          new = {
              "bar": "quux",
          }
          result = merge_context(old, new)
          assert result["foo"] == ["quux"], result
          assert result["bar"] == ["quux"], result
  