Keyerror: 1 when executing the below function

[jijumohan]

def plot_important_words(top_scores, top_words, bottom_scores, bottom_words, name):
y_pos = np.arange(len(top_words))
top_pairs = [(a,b) for a,b in zip(top_words, top_scores)]
top_pairs = sorted(top_pairs, key=lambda x: x[1])

bottom_pairs = [(a,b) for a,b in zip(bottom_words, bottom_scores)]
bottom_pairs = sorted(bottom_pairs, key=lambda x: x[1], reverse=True)

top_words = [a[0] for a in top_pairs]
top_scores = [a[1] for a in top_pairs]

bottom_words = [a[0] for a in bottom_pairs]
bottom_scores = [a[1] for a in bottom_pairs]

fig = plt.figure(figsize=(10, 10))  

plt.subplot(121)
plt.barh(y_pos,bottom_scores, align='center', alpha=0.5)
plt.title('Irrelevant', fontsize=20)
plt.yticks(y_pos, bottom_words, fontsize=14)
plt.suptitle('Key words', fontsize=16)
plt.xlabel('Importance', fontsize=20)

plt.subplot(122)
plt.barh(y_pos,top_scores, align='center', alpha=0.5)
plt.title('Disaster', fontsize=20)
plt.yticks(y_pos, top_words, fontsize=14)
plt.suptitle(name, fontsize=16)
plt.xlabel('Importance', fontsize=20)

plt.subplots_adjust(wspace=0.8)
plt.show()

top_scores = [a[0] for a in importance[1]['tops']]
top_words = [a[1] for a in importance[1]['tops']]
bottom_scores = [a[0] for a in importance[1]['bottom']]
bottom_words = [a[1] for a in importance[1]['bottom']]

plot_important_words(top_scores, top_words, bottom_scores, bottom_words, "Most important words for relevance")

Following is the erro
KeyError Traceback (most recent call last)
in ()
33
34
---> 35 bottom_scores =[a[1] for a in importance[1]['bottom']]
36 bottom_words = [a[0] for a in importance[1]['bottom']]
37 top_scores =[a[1] for a in importance[1]['tops']]

KeyError: 1