code: def test_copy(self):
      schema = TableSchema(
          ["a", "b", "c"],
          [DataTypes.INT(), DataTypes.BIGINT(), DataTypes.STRING()],
      )
  
      copied_schema = schema.copy()
  
      self.assertEqual(schema, copied_schema)
      copied_schema._j_table_schema = None
      self.assertNotEqual(schema, copied_schema)
  
file_path: flink/flink-python/pyflink/table/tests/test_table_schema.py
imports: from pyflink.table.types import DataTypes
  from pyflink.table.table_schema import TableSchema
  from pyflink.testing.test_case_utils import PyFlinkTestCase
label_desc: Use image node_id 2 for calling the TableSchemaTests obj's underlying member method code with example usage: obj.test_copy() without return types