class_docstr: A backfill job runner consists of a dag or subdag for a specific time range.
  
  It triggers a set of task instance runs, in the right order and lasts for
  as long as it takes for the set of task instance to be completed.
docstr: Compute and execute dag runs and their respective task instances for the given dates.
  
  Returns a list of execution dates of the dag runs that were executed.
  
  :param dagrun_infos: Schedule information for dag runs
  :param ti_status: internal BackfillJobRunner status structure to tis track progress
  :param executor: the executor to use, it must be previously started
  :param pickle_id: numeric id of the pickled dag, None if not pickled
  :param start_date: backfill start date
  :param session: the current session object
docstr_tok: ["Compute","and","execute","dag","runs","and","their","respective","task","instances","for","the","given","dates",".","Returns","a","list","of","execution","dates","of","the","dag","runs","that","were","executed",".",":","param","dagrun_infos",":","Schedule","information","for","dag","runs",":","param","ti_status",":","internal","BackfillJobRunner","status","structure","to","tis","track","progress",":","param","executor",":","the","executor","to","use",",","it","must","be","previously","started",":","param","pickle_id",":","numeric","id","of","the","pickled","dag",",","None","if","not","pickled",":","param","start_date",":","backfill","start","date",":","param","session",":","the","current","session","object"]
code: def _execute_dagruns(
      self,
      dagrun_infos: Iterable[DagRunInfo],
      ti_status: _DagRunTaskStatus,
      executor: BaseExecutor,
      pickle_id: int | None,
      start_date: datetime.datetime | None,
      session: Session = NEW_SESSION,
  ) -> None:
      """
      Compute and execute dag runs and their respective task instances for the given dates.
  
      Returns a list of execution dates of the dag runs that were executed.
  
      :param dagrun_infos: Schedule information for dag runs
      :param ti_status: internal BackfillJobRunner status structure to tis track progress
      :param executor: the executor to use, it must be previously started
      :param pickle_id: numeric id of the pickled dag, None if not pickled
      :param start_date: backfill start date
      :param session: the current session object
      """
      for dagrun_info in dagrun_infos:
          for dag in self._get_dag_with_subdags():
              dag_run = self._get_dag_run(
                  dagrun_info, dag, session=session
              )
              if dag_run is not None:
                  tis_map = self._task_instances_for_dag_run(
                      dag, dag_run, session=session
                  )
                  ti_status.active_runs.append(dag_run)
                  ti_status.to_run.update(tis_map or {})
  
      processed_dag_run_dates = self._process_backfill_task_instances(
          ti_status=ti_status,
          executor=executor,
          pickle_id=pickle_id,
          start_date=start_date,
          session=session,
      )
  
      ti_status.executed_dag_run_dates.update(processed_dag_run_dates)
  
imports: from __future__ import annotations
  import time
  from typing import TYPE_CHECKING, Any, Iterable, Iterator, Mapping, Sequence
  import attr
  import pendulum
  from sqlalchemy import select, tuple_, update
  from sqlalchemy.exc import OperationalError
  from sqlalchemy.orm.session import make_transient
  from tabulate import tabulate
  from airflow import models
  from airflow.exceptions import AirflowException, BackfillUnfinished, DagConcurrencyLimitReached, NoAvailablePoolSlot, PoolNotFound, TaskConcurrencyLimitReached
  from airflow.executors.executor_loader import ExecutorLoader
  from airflow.jobs.base_job_runner import BaseJobRunner
  from airflow.jobs.job import Job, perform_heartbeat
  from airflow.models import DAG, DagPickle
  from airflow.models.dagrun import DagRun
  from airflow.models.taskinstance import TaskInstance
  from airflow.ti_deps.dep_context import DepContext
  from airflow.ti_deps.dependencies_deps import BACKFILL_QUEUED_DEPS
  from airflow.timetables.base import DagRunInfo
  from airflow.utils import helpers, timezone
  from airflow.utils.configuration import conf, tmp_configuration_copy
  from airflow.utils.log.logging_mixin import LoggingMixin
  from airflow.utils.session import NEW_SESSION, provide_session
  from airflow.utils.state import DagRunState, State, TaskInstanceState
  from airflow.utils.types import DagRunType
label_desc: Use image node_id 10 for calling the BackfillJobRunner obj's underlying member method code with example usage: obj._execute_dagruns(dagrun_infos, ti_status, executor, pickle_id, start_date, session) without return types