Tensorflow &引用；ValueError：无不支持的值；在skflow示例中使用neural_translation.py

我的环境是

• Mac OS X 10.11.4
• Python 2.7
• 张量流量0.8

我刚刚在tensorflow中运行了一个skflow示例。 例子是

但是上面给出了以下错误

Traceback (most recent call last):
  File "neural_translation.py", line 121, in <module>
    translator.fit(x_iter, y_iter, logdir=PATH)
  File "/Library/Python/2.7/site-packages/tensorflow/contrib/learn/python/learn/estimators/base.py", line 227, in fit
    self._setup_training()
  File "/Library/Python/2.7/site-packages/tensorflow/contrib/learn/python/learn/estimators/base.py", line 163, in _setup_training
    optimizer=optimizer, clip_gradients=self.clip_gradients)
  File "/Library/Python/2.7/site-packages/tensorflow/contrib/layers/python/layers/optimizers.py", line 141, in optimize_loss
    logging_ops.histogram_summary(variable.name + "/gradients", grad_values)
  File "/Library/Python/2.7/site-packages/tensorflow/python/ops/logging_ops.py", line 113, in histogram_summary
    tag=tag, values=values, name=scope)
  File "/Library/Python/2.7/site-packages/tensorflow/python/ops/gen_logging_ops.py", line 55, in _histogram_summary
    name=name)
  File "/Library/Python/2.7/site-packages/tensorflow/python/ops/op_def_library.py", line 415, in apply_op
    as_ref=input_arg.is_ref).dtype.name
  File "/Library/Python/2.7/site-packages/tensorflow/python/framework/ops.py", line 566, in convert_to_tensor
    ret = conversion_func(value, dtype=dtype, name=name, as_ref=as_ref)
  File "/Library/Python/2.7/site-packages/tensorflow/python/ops/constant_op.py", line 179, in _constant_tensor_conversion_function
    return constant(v, dtype=dtype, name=name)
  File "/Library/Python/2.7/site-packages/tensorflow/python/ops/constant_op.py", line 162, in constant
    tensor_util.make_tensor_proto(value, dtype=dtype, shape=shape))
  File "/Library/Python/2.7/site-packages/tensorflow/python/framework/tensor_util.py", line 325, in make_tensor_proto
    raise ValueError("None values not supported.")
ValueError: None values not supported.

回溯（最近一次呼叫最后一次）：
文件“neural_translation.py”，第121行，在
fit（x_iter，y_iter，logdir=PATH）
文件“/Library/Python/2.7/site packages/tensorflow/contrib/learn/Python/learn/estimators/base.py”，第227行，适合
自我设置和培训（）
文件“/Library/Python/2.7/site packages/tensorflow/contrib/learn/Python/learn/estimators/base.py”，第163行，在“设置”培训中
优化器=优化器，clip\u渐变=self.clip\u渐变）
文件“/Library/Python/2.7/site packages/tensorflow/contrib/layers/Python/layers/optimizers.py”，第141行，在optimize_loss中
记录操作直方图摘要（variable.name+“/gradients”，梯度值）
文件“/Library/Python/2.7/site packages/tensorflow/Python/ops/logging_ops.py”，第113行，在直方图摘要中
标记=标记，值=值，名称=范围）
文件“/Library/Python/2.7/site packages/tensorflow/Python/ops/gen_logging_ops.py”，第55行，在“直方图”摘要中
名称=名称）
文件“/Library/Python/2.7/site packages/tensorflow/Python/ops/op_def_Library.py”，第415行，在apply_op中
as_ref=输入参数为.dtype.name
文件“/Library/Python/2.7/site packages/tensorflow/Python/framework/ops.py”，第566行，在convert_to_tensor中
ret=conversion\u func（值，dtype=dtype，name=name，as\u ref=as\u ref）
文件“/Library/Python/2.7/site packages/tensorflow/Python/ops/constant_op.py”，第179行，在_constant_tensor_conversion_函数中
返回常量（v，dtype=dtype，name=name）
文件“/Library/Python/2.7/site packages/tensorflow/Python/ops/constant_op.py”，第162行，常量
tensor_util.make_tensor_proto（值，dtype=dtype，shape=shape））
make_tensor_proto中的文件“/Library/Python/2.7/site packages/tensorflow/Python/framework/tensor_util.py”，第325行
raise VALUERROR（“不支持无值”）
ValueError:不支持任何值。

有人知道如何解决这个错误吗？先谢谢你

Traceback (most recent call last):
  File "neural_translation.py", line 121, in <module>
    translator.fit(x_iter, y_iter, logdir=PATH)
  File "/Library/Python/2.7/site-packages/tensorflow/contrib/learn/python/learn/estimators/base.py", line 227, in fit
    self._setup_training()
  File "/Library/Python/2.7/site-packages/tensorflow/contrib/learn/python/learn/estimators/base.py", line 163, in _setup_training
    optimizer=optimizer, clip_gradients=self.clip_gradients)
  File "/Library/Python/2.7/site-packages/tensorflow/contrib/layers/python/layers/optimizers.py", line 141, in optimize_loss
    logging_ops.histogram_summary(variable.name + "/gradients", grad_values)
  File "/Library/Python/2.7/site-packages/tensorflow/python/ops/logging_ops.py", line 113, in histogram_summary
    tag=tag, values=values, name=scope)
  File "/Library/Python/2.7/site-packages/tensorflow/python/ops/gen_logging_ops.py", line 55, in _histogram_summary
    name=name)
  File "/Library/Python/2.7/site-packages/tensorflow/python/ops/op_def_library.py", line 415, in apply_op
    as_ref=input_arg.is_ref).dtype.name
  File "/Library/Python/2.7/site-packages/tensorflow/python/framework/ops.py", line 566, in convert_to_tensor
    ret = conversion_func(value, dtype=dtype, name=name, as_ref=as_ref)
  File "/Library/Python/2.7/site-packages/tensorflow/python/ops/constant_op.py", line 179, in _constant_tensor_conversion_function
    return constant(v, dtype=dtype, name=name)
  File "/Library/Python/2.7/site-packages/tensorflow/python/ops/constant_op.py", line 162, in constant
    tensor_util.make_tensor_proto(value, dtype=dtype, shape=shape))
  File "/Library/Python/2.7/site-packages/tensorflow/python/framework/tensor_util.py", line 325, in make_tensor_proto
    raise ValueError("None values not supported.")
ValueError: None values not supported.