How to use the pysoa.client.expander.ExpansionNode function in pysoa

trees = self.converter.dict_to_trees({
            'foo': [
                'bar',
                'bar.baz',
                'bar.qux',
            ],
        })

        self.assertEqual(len(trees), 1)
        type_node = trees[0]
        self.assertIsInstance(type_node, TypeNode)
        self.assertEqual(type_node.type, 'foo')
        self.assertEqual(len(type_node.expansions), 1)

        bar_expansion_node = type_node.expansions[0]
        self.assertIsInstance(bar_expansion_node, ExpansionNode)
        self.assertEqual(bar_expansion_node.type, 'bar')
        self.assertEqual(bar_expansion_node.name, 'bar')
        self.assertEqual(bar_expansion_node.source_field, 'bar_id')
        self.assertEqual(bar_expansion_node.destination_field, 'bar')
        self.assertEqual(bar_expansion_node.service, 'bar')
        self.assertEqual(bar_expansion_node.action, 'get_bar')
        self.assertEqual(bar_expansion_node.request_field, 'id')
        self.assertEqual(bar_expansion_node.response_field, 'bar')
        self.assertEqual(len(bar_expansion_node.expansions), 2)

        baz_expansion_node, qux_expansion_node = sorted(bar_expansion_node.expansions, key=lambda x: x.type)
        self.assertIsInstance(baz_expansion_node, ExpansionNode)
        self.assertEqual(baz_expansion_node.type, 'baz')
        self.assertEqual(baz_expansion_node.name, 'baz')
        self.assertEqual(baz_expansion_node.source_field, 'baz_id')
        self.assertEqual(baz_expansion_node.destination_field, 'baz')

def test_to_dict(self):
        bar_expansion_node = ExpansionNode(
            node_type='bar',
            name='bar',
            source_field='bar_id',
            destination_field='bar',
            service='bar',
            action='get_bar',
            request_field='id',
            response_field='bar',
        )
        baz_expansion_node = ExpansionNode(
            node_type='baz',
            name='baz',
            source_field='baz_id',
            destination_field='baz',
            service='baz',
            action='get_baz',

def setUp(self):
        self.expansion_node = ExpansionNode(
            node_type='foo',
            name='foo',
            source_field='foo_id',
            destination_field='foo',
            service='foo',
            action='get_foo',
            request_field='id',
            response_field='foo',
        )

def test_to_strings_with_expansions(self):
        bar_expansion_node = ExpansionNode(
            node_type='bar',
            name='bar',
            source_field='bar_id',
            destination_field='bar',
            service='bar',
            action='get_bar',
            request_field='id',
            response_field='bar',
        )
        baz_expansion_node = ExpansionNode(
            node_type='baz',
            name='baz',
            source_field='baz_id',
            destination_field='baz',
            service='baz',
            action='get_baz',
            request_field='id',
            response_field='baz',
        )
        self.expansion_node.add_expansion(bar_expansion_node)
        self.expansion_node.add_expansion(baz_expansion_node)

        self.assertEqual(
            set(self.expansion_node.to_strings()),
            {'foo.baz', 'foo.bar'},
        )

def test_to_strings_with_expansions(self):
        bar_expansion_node = ExpansionNode(
            node_type='bar',
            name='bar',
            source_field='bar_id',
            destination_field='bar',
            service='bar',
            action='get_bar',
            request_field='id',
            response_field='bar',
        )
        baz_expansion_node = ExpansionNode(
            node_type='baz',
            name='baz',
            source_field='baz_id',
            destination_field='baz',
            service='baz',
            action='get_baz',

service='bar',
            action='get_bar',
            request_field='id',
            response_field='bar',
        )
        baz_expansion_node = ExpansionNode(
            node_type='baz',
            name='baz',
            source_field='baz_id',
            destination_field='baz',
            service='baz',
            action='get_baz',
            request_field='id',
            response_field='baz',
        )
        qux_expansion_node = ExpansionNode(
            node_type='qux',
            name='qux',
            source_field='qux_id',
            destination_field='qux',
            service='qux',
            action='get_qux',
            request_field='id',
            response_field='qux',
        )
        bar_expansion_node.add_expansion(baz_expansion_node)
        bar_expansion_node.add_expansion(qux_expansion_node)
        self.type_node.add_expansion(bar_expansion_node)

        type_node_dict = self.type_node.to_dict()

        self.assertTrue('foo' in type_node_dict)

def test_get_expansion(self):
        expansion_node = ExpansionNode(
            node_type='bar',
            name='bar',
            source_field='bar_id',
            destination_field='bar',
            service='bar',
            action='get_bar',
            request_field='id',
            response_field='bar',
        )
        self.type_node.add_expansion(expansion_node)
        self.assertEqual(
            self.type_node.get_expansion(expansion_node.name),
            expansion_node,
        )

def test_cannot_add_same_expansion_twice(self):
        expansion_node = ExpansionNode(
            node_type='bar',
            name='bar',
            source_field='bar_id',
            destination_field='bar',
            service='bar',
            action='get_bar',
            request_field='id',
            response_field='bar',
        )
        self.type_node.add_expansion(expansion_node)
        self.type_node.add_expansion(expansion_node)

        self.assertEqual(len(self.type_node.expansions), 1)
        self.assertEqual(
            self.type_node.expansions[0],
            expansion_node,

def test_trees_to_dict(self):
        foo_tree_node = TypeNode(node_type='foo')
        bar_expansion_node = ExpansionNode(
            node_type='bar',
            name='bar',
            source_field='bar_id',
            destination_field='bar',
            service='bar',
            action='get_bar',
            request_field='id',
            response_field='bar',
        )
        foo_tree_node.add_expansion(bar_expansion_node)

        baz_tree_node = TypeNode(node_type='baz')
        qux_expansion_node = ExpansionNode(
            node_type='qux',
            name='qux',
            source_field='qux_id',

for expansion_string in expansion_list:
                expansion_node = type_node

                for expansion_name in expansion_string.split('.'):
                    child_expansion_node = expansion_node.get_expansion(expansion_name)

                    if not child_expansion_node:
                        type_expansion = self.type_expansions[expansion_node.type][expansion_name]
                        type_route = self.type_routes[cast(six.text_type, type_expansion['route'])]
                        if type_expansion['destination_field'] == type_expansion['source_field']:
                            raise ValueError(
                                'Expansion configuration destination_field error: '
                                'destination_field can not have the same name as the source_field: '
                                '{}'.format(type_expansion['source_field'])
                            )
                        child_expansion_node = ExpansionNode(
                            node_type=cast(six.text_type, type_expansion['type']),
                            name=expansion_name,
                            source_field=cast(six.text_type, type_expansion['source_field']),
                            destination_field=cast(six.text_type, type_expansion['destination_field']),
                            service=type_route['service'],
                            action=type_route['action'],
                            request_field=type_route['request_field'],
                            response_field=type_route['response_field'],
                            raise_action_errors=cast(bool, type_expansion.get('raise_action_errors', False)),
                        )
                        expansion_node.add_expansion(child_expansion_node)

                    expansion_node = child_expansion_node

            trees.append(type_node)