TypeError: unsupported operand type(s) for /: 'NoneType' and 'float' AND AttributeError: module 'tensorflow' has no attribute 'placeholder'

[shotXD]

after executing gen.py and train.py it creates a couple of files generated in test folder but gives following error. Please help.

python3 gen.py

test/00000000_LTL8260_0.jpg
test/00000001_YGP2593_1.jpg
Traceback (most recent call last):
File "gen.py", line 284, in
for img_idx, (im, c, p) in enumerate(im_gen):
File "gen.py", line 275, in generate_ims
yield generate_im(font_char_ims[random.choice(fonts)], num_bg_images)
File "gen.py", line 230, in generate_im
bg = generate_bg(num_bg_images)
File "gen.py", line 217, in generate_bg
bg = cv2.imread(fname, 0) / 255.
TypeError: unsupported operand type(s) for /: 'NoneType' and 'float'

---

python3 train.py
Train start! 2020-04-14 00:11:01
Traceback (most recent call last):
File "train.py", line 251, in
initial_weights=initial_weights)
File "train.py", line 156, in train
x, y, params = model.get_training_model()
File "/home/utsav/Downloads/LPR ALL/ANPR-Tensorflow/anpr/model.py", line 103, in get_training_model
x, conv_layer, conv_vars = convolutional_layers()
File "/home/utsav/Downloads/LPR ALL/ANPR-Tensorflow/anpr/model.py", line 66, in convolutional_layers
x = tf.placeholder(tf.float32, [None, None, None])
AttributeError: module 'tensorflow' has no attribute 'placeholder'

[pendex900x]

!pip install matplotlib==2.1.2
!pip install opencv-python==3.1.0.5
!pip install Pillow==5.3.0
!pip install numpy==1.14.4

!python -m pip install --upgrade tensorflow==1.8.0