code: def test_visit_should_call_explain(self):
      stmt = MagicMock(spec=ExplainStatement)
      converter = StatementToPlanConverter()
      mock = MagicMock()
      converter.visit_explain = mock
  
      converter.visit(stmt)
      mock.assert_called_once()
      mock.assert_called_once_with(stmt)
  
imports: import unittest
  from inspect import signature
  from test.util import get_all_subclasses
  from mock import MagicMock, patch
  from evadb.optimizer.operators import Dummy, LogicalApplyAndMerge, LogicalCreate, LogicalCreateFunction, LogicalCreateIndex, LogicalDelete, LogicalDropObject, LogicalExchange, LogicalExplain, LogicalExtractObject, LogicalFilter, LogicalFunctionScan, LogicalGet, LogicalGroupBy, LogicalInsert, LogicalJoin, LogicalLimit, LogicalLoadData, LogicalOrderBy, LogicalProject, LogicalQueryDerivedGet, LogicalRename, LogicalSample, LogicalShow, LogicalUnion, LogicalVectorIndexScan, Operator
  from evadb.optimizer.statement_to_opr_converter import StatementToPlanConverter
  from evadb.parser.create_function_statement import CreateFunctionStatement
  from evadb.parser.create_index_statement import CreateIndexStatement
  from evadb.parser.create_statement import CreateTableStatement
  from evadb.parser.drop_object_statement import DropObjectStatement
  from evadb.parser.explain_statement import ExplainStatement
  from evadb.parser.insert_statement import InsertTableStatement
  from evadb.parser.rename_statement import RenameTableStatement
  from evadb.parser.select_statement import SelectStatement
  from evadb.parser.table_ref import TableRef
label_desc: Use image node_id 14 for calling the StatementToOprTest obj's underlying member method code with example usage: obj.test_visit_should_call_explain() without return types