failing code snippet for multiple models

failing_cod.py

import numpy as np
from keras.models import Sequential
from keras.callbacks import TensorBoard
from keras.layers import *
from keras.optimizers import *

N=10
INPUT_LEN = 4
OUTPUT_LEN = 2

def make_model(model):
	model.add(Dense(units=8, activation='relu', input_dim=INPUT_LEN))
	model.add(Dense(units=OUTPUT_LEN, activation='linear'))
	model.compile(loss='categorical_crossentropy', optimizer='adam')


model1 = Sequential()

model2 = Sequential()

make_model(model1)
make_model(model2)

print(model1.summary())
print(model2.summary())

x = np.random.rand(N, INPUT_LEN)
y = np.random.randint(0,5, size=(N,OUTPUT_LEN))
print("x shape: {}".format(x.shape))
print("y shape: {}".format(y.shape))

model1.fit(x, y, callbacks=[TensorBoard(log_dir='./tmp', histogram_freq=1)], epochs=10, validation_data=(x,y))
model2.fit(x, y, callbacks=[TensorBoard(log_dir='./tmp', histogram_freq=1)], epochs=10, validation_data=(x,y))