UnboundLocalError: local variable 'ret' referenced before assignmentを解決したいです。

実現したいこと

UnboundLocalError: local variable 'ret' referenced before assignmentのエラーを解決したいです。

10-20、44-49行目で変数retに対して代入が行われているはずですが、分かりません。

前提

DCLGAN実装中に以下のエラーメッセージが発生しました。

発生している問題・エラーメッセージ

Traceback (most recent call last):
  File "train.py", line 14, in <module>
    model = create_model(opt)      # create a model given opt.model and other options
  File "C:\Users\DCLGAN-main\models\__init__.py", line 65, in create_model
    instance = model(opt)
  File "C:\Users\DCLGAN-main\models\dcl_model.py", line 102, in __init__
    self.criterionSim = torch.nn.L1Loss('sum').to(self.device)
  File "C:\Users\rt-pc\anaconda3\envs\DCLGAN\lib\site-packages\torch\nn\modules\loss.py", line 90, in __init__
    super(L1Loss, self).__init__(size_average, reduce, reduction)
  File "C:\Users\rt-pc\anaconda3\envs\DCLGAN\lib\site-packages\torch\nn\modules\loss.py", line 17, in __init__
    self.reduction = _Reduction.legacy_get_string(size_average, reduce)
  File "C:\Users\rt-pc\anaconda3\envs\DCLGAN\lib\site-packages\torch\nn\_reduction.py", line 44, in legacy_get_string
    warnings.warn(warning.format(ret))
UnboundLocalError: local variable 'ret' referenced before assignment

該当のソースコード

import warnings
from typing import Optional

# NB: Keep this file in sync with enums in aten/src/ATen/core/Reduction.h


def get_enum(reduction):
    # type: (str) -> int
    if reduction == 'none':
        ret = 0
    elif reduction == 'mean':
        ret = 1
    elif reduction == 'elementwise_mean':
        warnings.warn("reduction='elementwise_mean' is deprecated, please use reduction='mean' instead.")
        ret = 1
    elif reduction == 'sum':
        ret = 2
    else:
        ret = -1  # TODO: remove once JIT exceptions support control flow
        raise ValueError("{} is not a valid value for reduction".format(reduction))
    return ret

# In order to support previous versions, accept boolean size_average and reduce
# and convert them into the new constants for now


# We use these functions in torch/legacy as well, in which case we'll silence the warning
def legacy_get_string(size_average, reduce, emit_warning=True):
    # type: (Optional[bool], Optional[bool], bool) -> str
    warning = "size_average and reduce args will be deprecated, please use reduction='{}' instead."

    if size_average is None:
        size_average = True
    if reduce is None:
        reduce = True

    if size_average and reduce:
        reduce = 'mean'
    elif reduce:
        ret = 'sum'
    else:
        ret = 'none'
    if emit_warning:
        warnings.warn(warning.format(ret))
    return ret


def legacy_get_enum(size_average, reduce, emit_warning=True):
    # type: (Optional[bool], Optional[bool], bool) -> int
    return get_enum(legacy_get_string(size_average, reduce, emit_warning))