code: def unmarkQueryVar(where):
      if isinstance(where, BinaryOperation):
          unmarkQueryVar(where.args[0])
          unmarkQueryVar(where.args[1])
      elif isinstance(where, UnaryOperation):
          unmarkQueryVar(where.args[0])
      elif isinstance(where, Constant):
          if hasattr(where, "is_var") and where.is_var is True:
              where.value = where.var_name
  
file_path: mindsdb/mindsdb/api/executor/sql_query/steps/map_reduce_step.py
imports: import copy
  from mindsdb_sql.parser.ast import BinaryOperation, UnaryOperation, Constant
  from mindsdb_sql.planner.steps import MapReduceStep, FetchDataframeStep, MultipleSteps
  from mindsdb.api.executor.sql_query.result_set import ResultSet
  from mindsdb.api.executor.exceptions import LogicError
  from .base import BaseStepCall
  from .fetch_dataframe import FetchDataframeStepCall
label_desc: Use image node_id 2 for calling a global function with example usage: unmarkQueryVar(where) without return types