class_docstr: Abstract base class of all samplers.
  
  Implementations of this class should override `construct`,
  `obtain_samples`, and `shutdown_worker`. `construct` takes a
  `WorkerFactory`, which implements most of the RL-specific functionality a
  `Sampler` needs. Specifically, it specifies how to construct `Worker`s,
  which know how to collect episodes and update both agents and environments.
  
  Currently, `__init__` is also part of the interface, but calling it is
  deprecated. `start_worker` is also deprecated, and does not need to be
  implemented.
docstr: Initialize the sampler.
  
  i.e. launching parallel workers if necessary.
  
  This method is deprecated, please launch workers in construct instead.
code: def start_worker(self):
      """Initialize the sampler.
  
      i.e. launching parallel workers if necessary.
  
      This method is deprecated, please launch workers in construct instead.
      """
  
file_path: garage/src/garage/sampler/sampler.py
imports: import abc
  import copy
label_desc: Use image node_id 3 for calling the Sampler obj's underlying member method code with example usage: obj.start_worker() without return types