code: def test_no_schema(self):
      descriptor = TableDescriptor.for_connector(
          "test-connector"
      ).build()
      self.assertIsNone(descriptor.get_schema())
  
file_path: flink/flink-python/pyflink/table/tests/test_table_descriptor.py
imports: from pyflink.common.config_options import ConfigOptions
  from pyflink.table import DataTypes
  from pyflink.table.schema import Schema
  from pyflink.table.table_descriptor import TableDescriptor, FormatDescriptor
  from pyflink.testing.test_case_utils import PyFlinkStreamTableTestCase
label_desc: Use image node_id 3 for calling the TableDescriptorTest obj's underlying member method code with example usage: obj.test_no_schema() without return types