NameError: name 'model' is not defined

# Show History

model.evaluate(x_test,  y_test, verbose=2)

import matplotlib.pyplot as plt

fig, loss_ax = plt.subplots()

fig, acc_ax = plt.subplots()

loss_ax.plot(history.history['loss'], 'ro', label='train loss')

loss_ax.plot(history.history['val_loss'], 'r:', label='val loss')

loss_ax.set_xlabel('epoch')

loss_ax.set_ylabel('loss')

loss_ax.legend(loc='upper left')

acc_ax.plot(history.history['accuracy'], 'bo', label='train accuracy')

acc_ax.plot(history.history['val_accuracy'], 'b:', label='val accuracy')

acc_ax.set_ylabel('accuracy')

acc_ax.legend(loc='upper left')

plt.show()

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-22-ba2619a0447f> in <module>
      1 # Show History
----> 2 model.evaluate(x_test,  y_test, verbose=2)
      3 
      4 import matplotlib.pyplot as plt
      5 

NameError: name 'model' is not defined