AttributeError: module 'tensorflow' has no attribute 'get_default_graph'

[ChasingWind]

I had this issue:
AttributeError: module 'tensorflow' has no attribute 'get_default_graph'
Then I asked for help online.I knowed tensorflow and keras may be not compatible .
So I replaced :
import keras
with :
from tensorflow import keras
replaced:
from keras.someing import someting
with:
from tensorflow .keras.someing import someting .
Then the issue changed:
from tensorflow.keras.layers import Dense, Dropout, Merge, Input
ImportError: cannot import name 'Merge
So what should I do to deal with is?What version of tf and keras do you use ? I use Keras 2.1.0 and tensorflow 2.1.0. How to deal with that tensorflow and keras arenot compatible ?
Looking forward to your reply.Thank you