AttributeError: module 'tensorflow.python._pywrap_tensorflow_internal' has no attribute '_NewStatSummarizer'

Question

I am trying to install TensorFlow object detection from this link.

But in the testing step when I write:

python object_detection/builders/model_builder_test.py

I get the following error:

line 354, in <module>
    _NewStatSummarizer = _pywrap_tensorflow_internal._NewStatSummarizer
AttributeError: module 'tensorflow.python._pywrap_tensorflow_internal' has no attribute '_NewStatSummarizer'

Could any one help me, please?

I'm using Tensorflow 1.9.0 with Python 3.5.

Thank you in advance!