code: def call(self, step):
      result = self.steps_data[step.dataframe.step_num]
  
      table_name = step.table_name
      if table_name is None:
          table_name = "df_table"
      else:
          table_name = table_name
  
      query = step.query
      query.from_table = Identifier("df_table")
  
      if step.add_absent_cols and isinstance(query, Select):
          query_cols = set()
  
          def f_all_cols(node, **kwargs):
              if isinstance(node, Identifier):
                  query_cols.add(node.parts[-1])
  
          query_traversal(query.where, f_all_cols)
  
          result_cols = [col.name for col in result.columns]
  
          for col_name in query_cols:
              if col_name not in result_cols:
                  result.add_column(Column(col_name))
  
      df = result.to_df()
      res = query_df(df, query)
  
      result2 = ResultSet()
      # get database from first column
      database = result.columns[0].database
      result2.from_df(res, database, table_name)
  
      return result2
  
file_path: mindsdb/mindsdb/api/executor/sql_query/steps/subselect_step.py
imports: from mindsdb_sql.parser.ast import Identifier, Select
  from mindsdb_sql.planner.steps import SubSelectStep
  from mindsdb_sql.planner.utils import query_traversal
  from mindsdb.api.executor.sql_query.result_set import ResultSet, Column
  from mindsdb.api.executor.utilities.sql import query_df
  from .base import BaseStepCall
label_desc: Use image node_id 1 for calling the SubSelectStepCall obj's underlying member method code with example usage: obj.call(step) and returns: result2