indexes of graph outputs that should be quantized
         "preserved_attributes": a list of attributes that persist
         even if they are not used in "forward"
  This function is primarily for backward compatibility and may be
  removed in the future.

  Return type:
     *PrepareCustomConfig*

set_float_to_observed_mapping(float_class, observed_class, quant_type=QuantType.STATIC)
  Set the mapping from a custom float module class to a custom
  observed module class.

  The observed module class must have a "from_float" class method
  that converts the float module class to the observed module
  class. This is currently only supported for static quantization.

  Return type:
     *PrepareCustomConfig*

set_input_quantized_indexes(indexes)
  Set the indexes of the inputs of the graph that should be
  quantized. Inputs are otherwise assumed to be in fp32 by default
  instead.

  Return type:
     *PrepareCustomConfig*
