[警告] [TensorFlow] Cause: module 'gast' has no attribute 'Num'

警告信息

WARNING:tensorflow:Entity <bound method TensorFlowOpLayer._defun_call of <tensorflow.python.eager.function.TfMethodTarget object at 0x000001805B549780>> could not be transformed and will be executed as-is. Please report this to the AutoGraph team. When filing the bug, set the verbosity to 10 (on Linux, `export AUTOGRAPH_VERBOSITY=10`) and attach the full output. Cause: Bad argument number for Name: 3, expecting 4
WARNING:tensorflow:Entity <bound method TensorFlowOpLayer._defun_call of <tensorflow.python.eager.function.TfMethodTarget object at 0x000001805B549A58>> could not be transformed and will be executed as-is. Please report this to the AutoGraph team. When filing the bug, set the verbosity to 10 (on Linux, `export AUTOGRAPH_VERBOSITY=10`) and attach the full output. Cause: Bad argument number for Name: 3, expecting 4
WARNING:tensorflow:Entity <bound method TensorFlowOpLayer._defun_call of <tensorflow.python.eager.function.TfMethodTarget object at 0x0000018053049C18>> could not be transformed and will be executed as-is. Please report this to the AutoGraph team. When filing the bug, set the verbosity to 10 (on Linux, `export AUTOGRAPH_VERBOSITY=10`) and attach the full output. Cause: Bad argument number for Name: 3, expecting 4
WARNING:tensorflow:Entity <bound method TensorFlowOpLayer._defun_call of <tensorflow.python.eager.function.TfMethodTarget object at 0x0000018051AAFC50>> could not be transformed and will be executed as-is. Please report this to the AutoGraph team. When filing the bug, set the verbosity to 10 (on Linux, `export AUTOGRAPH_VERBOSITY=10`) and attach the full output. Cause: Bad argument number for Name: 3, expecting 4
WARNING:tensorflow:Entity <bound method TensorFlowOpLayer._defun_call of <tensorflow.python.eager.function.TfMethodTarget object at 0x0000018051AC6B00>> could not be transformed and will be executed as-is. Please report this to the AutoGraph team. When filing the bug, set the verbosity to 10 (on Linux, `export AUTOGRAPH_VERBOSITY=10`) and attach the full output. Cause: Bad argument number for Name: 3, expecting 4
WARNING:tensorflow:Entity <bound method TensorFlowOpLayer._defun_call of <tensorflow.python.eager.function.TfMethodTarget object at 0x000001807CD9DBE0>> could not be transformed and will be executed as-is. Please report this to the AutoGraph team. When filing the bug, set the verbosity to 10 (on Linux, `export AUTOGRAPH_VERBOSITY=10`) and attach the full output. Cause: Bad argument number for Name: 3, expecting 4
WARNING:tensorflow:Entity <bound method TensorFlowOpLayer._defun_call of <tensorflow.python.eager.function.TfMethodTarget object at 0x0000018051AA6208>> could not be transformed and will be executed as-is. Please report this to the AutoGraph team. When filing the bug, set the verbosity to 10 (on Linux, `export AUTOGRAPH_VERBOSITY=10`) and attach the full output. Cause: Bad argument number for Name: 3, expecting 4
WARNING:tensorflow:Entity <bound method TensorFlowOpLayer._defun_call of <tensorflow.python.eager.function.TfMethodTarget object at 0x0000018051AA6748>> could not be transformed and will be executed as-is. Please report this to the AutoGraph team. When filing the bug, set the verbosity to 10 (on Linux, `export AUTOGRAPH_VERBOSITY=10`) and attach the full output. Cause: Bad argument number for Name: 3, expecting 4
WARNING:tensorflow:Entity <bound method TensorFlowOpLayer._defun_call of <tensorflow.python.eager.function.TfMethodTarget object at 0x000001804CB62E10>> could not be transformed and will be executed as-is. Please report this to the AutoGraph team. When filing the bug, set the verbosity to 10 (on Linux, `export AUTOGRAPH_VERBOSITY=10`) and attach the full output. Cause: Bad argument number for Name: 3, expecting 4
WARNING:tensorflow:Entity <bound method TensorFlowOpLayer._defun_call of <tensorflow.python.eager.function.TfMethodTarget object at 0x000001805A1B8F60>> could not be transformed and will be executed as-is. Please report this to the AutoGraph team. When filing the bug, set the verbosity to 10 (on Linux, `export AUTOGRAPH_VERBOSITY=10`) and attach the full output. Cause: Bad argument number for Name: 3, expecting 4
WARNING:tensorflow:Entity <bound method TensorFlowOpLayer._defun_call of <tensorflow.python.eager.function.TfMethodTarget object at 0x00000180530F16A0>> could not be transformed and will be executed as-is. Please report this to the AutoGraph team. When filing the bug, set the verbosity to 10 (on Linux, `export AUTOGRAPH_VERBOSITY=10`) and attach the full output. Cause: Bad argument number for Name: 3, expecting 4
WARNING:tensorflow:Entity <bound method TensorFlowOpLayer._defun_call of <tensorflow.python.eager.function.TfMethodTarget object at 0x0000018051AD1080>> could not be transformed and will be executed as-is. Please report this to the AutoGraph team. When filing the bug, set the verbosity to 10 (on Linux, `export AUTOGRAPH_VERBOSITY=10`) and attach the full output. Cause: Bad argument number for Name: 3, expecting 4

系统环境

• TensorFlow 2.0.0rc1
• Windows 10
• gast 0.3.2

解决方案

大约在每次调用model.fit或model.evaluate等函数时，会莫名有如上警告。
根据网友 ravikyram [1] 的建议，降低库gast的版本可解决此问题：

pip install gast==0.2.2

Reference

1. ravikyram. (September 10, 2019). TF2.0 AutoGraph issue. Retrieved from https://github.com/tensorflow/tensorflow/issues/32377