code: def generate_packer_filename(provider, region, builder):
      
      filename = '{0}_{1}_{2}.json'.format(provider, region, builder)
      return filename
docs: Generate a filename to be used by packer.
  
      Args:
          provider (str): Name of Spinnaker provider.
          region (str): Name of provider region to use.
          builder (str): Name of builder process type.
  
      Returns:
          str: Generated filename based on parameters.