code: def _validate_distribution_strategy(distribution_strategy):
      """Validates distribution strategy param."""
      if distribution_strategy not in ["auto", None]:
          raise ValueError(
              "Invalid `distribution_strategy` input. "
              'Expected "auto" or None. '
              "Received {}.".format(distribution_strategy)
          )
  
file_path: cloud/src/python/tensorflow_cloud/core/validate.py
imports: import os
  from .None import gcp
  from .None import machine_config
label_desc: Use image node_id 3 for calling a global function with example usage: _validate_distribution_strategy(distribution_strategy) without return types