class_docstr: Visits the SQL query plan to simplify sub-queries. On each visit, return a simplified node.
  
  Unlike SqlSubQueryReducerVisitor, this will re-write expressions to realize more reductions.
code: def _select_columns_contain_string_expressions(
      select_columns: Tuple[SqlSelectColumn, ...]
  ) -> bool:
      combined_lineage = SqlExpressionTreeLineage.combine(
          tuple(x.expr.lineage for x in select_columns)
      )
  
      return len(combined_lineage.string_exprs) > 0
  
imports: from __future__ import annotations
  import logging
  from dataclasses import dataclass
  from typing import List, Optional, Sequence, Tuple
  from metricflow.sql.optimizer.sql_query_plan_optimizer import SqlQueryPlanOptimizer
  from metricflow.sql.sql_exprs import SqlColumnAliasReferenceExpression, SqlColumnReference, SqlColumnReplacements, SqlExpressionNode, SqlExpressionTreeLineage, SqlLogicalExpression, SqlLogicalOperator
  from metricflow.sql.sql_plan import SqlJoinDescription, SqlOrderByDescription, SqlQueryPlanNode, SqlQueryPlanNodeVisitor, SqlSelectColumn, SqlSelectQueryFromClauseNode, SqlSelectStatementNode, SqlTableFromClauseNode
label_desc: Use image node_id 3 for calling the SqlRewritingSubQueryReducerVisitor obj's underlying member method code with example usage: obj._select_columns_contain_string_expressions(select_columns) and returns: unknown