docstr: Instantiates a ResNeXt from a configuration.
  
  Args:
      config: A configuration for a ResNeXt.
          See :func:`__init__` for parameters expected in the config.
  
  Returns:
      A ResNeXt instance.
docstr_tok: ["Instantiates","a","ResNeXt","from","a","configuration",".","Args",":","config",":","A","configuration","for","a","ResNeXt",".","See",":","func",":","`","__init__","`","for","parameters","expected","in","the","config",".","Returns",":","A","ResNeXt","instance","."]
code: def from_config(cls, config: Dict[str, Any]) -> "ResNeXt":
      """Instantiates a ResNeXt from a configuration.
  
      Args:
          config: A configuration for a ResNeXt.
              See :func:`__init__` for parameters expected in the config.
  
      Returns:
          A ResNeXt instance.
      """
      assert "num_blocks" in config
  
      basic_layer = config.get("basic_layer", False)
      config = {
          "num_blocks": config["num_blocks"],
          "init_planes": config.get("init_planes", 64),
          "reduction": config.get("reduction", 1 if basic_layer else 4),
          "base_width_and_cardinality": config.get(
              "base_width_and_cardinality"
          ),
          "small_input": config.get("small_input", False),
          "basic_layer": basic_layer,
          "final_bn_relu": config.get("final_bn_relu", True),
          "zero_init_bn_residuals": config.get(
              "zero_init_bn_residuals", False
          ),
          "use_se": config.get("use_se", False),
          "se_reduction_ratio": config.get("se_reduction_ratio", 16),
      }
      return cls(**config)
  
imports: import copy
  import math
  import re
  import warnings
  from collections import OrderedDict
  from typing import Any, Dict, Optional, Sequence
  import torch.nn
  from classy_vision.generic.util import is_pos_int, is_pos_int_tuple
  from .None import register_model
  from .classy_model import ClassyModel
  from .squeeze_and_excitation_layer import SqueezeAndExcitationLayer
label_desc: Use image node_id 5 for calling the ResNeXt obj's underlying member method code with example usage: obj.from_config(cls, config) and returns: cls