class_docstr: Abstract class for executors, which implement physical operator execution.
  
  Subclasses:
      StreamingExecutor
docstr: Start execution.
  
  Args:
      dag: The operator graph to execute.
      initial_stats: The DatasetStats to prepend to the stats returned by the
          executor. These stats represent actions done to compute inputs.
docstr_tok: ["Start","execution",".","Args",":","dag",":","The","operator","graph","to","execute",".","initial_stats",":","The","DatasetStats","to","prepend","to","the","stats","returned","by","the","executor",".","These","stats","represent","actions","done","to","compute","inputs","."]
code: def execute(
      self,
      dag: PhysicalOperator,
      initial_stats: Optional[DatasetStats] = None,
  ) -> OutputIterator:
      """Start execution.
  
      Args:
          dag: The operator graph to execute.
          initial_stats: The DatasetStats to prepend to the stats returned by the
              executor. These stats represent actions done to compute inputs.
      """
      raise NotImplementedError
  
file_path: ray/python/ray/data/_internal/execution/interfaces/executor.py
imports: from typing import Iterable, Iterator, Optional
  from .execution_options import ExecutionOptions
  from .physical_operator import PhysicalOperator
  from .ref_bundle import RefBundle
  from ray.data._internal.stats import DatasetStats
label_desc: Use image node_id 2 for calling the Executor obj's underlying member method code with example usage: obj.execute(dag, initial_stats) without return types