import re
 
def sentence_case(text):
	# Split into sentences. Therefore, find all text that ends
	# with punctuation followed by white space or end of string.
	sentences = re.findall('[^.!?]+[.!?](?:\s|\Z)', text)
 
	# Capitalize the first letter of each sentence
	sentences = [x[0].upper() + x[1:] for x in sentences]
 
	# Combine sentences
	return ''.join(sentences)
 
text = 'hello world. i know you hear me! where are you?'
print(text)
print(sentence_case(text))
 

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