Number of Valid Words in a Sentence LeetCode solution in Python

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import re
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class Solution:
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    def countValidWords(self, sentence: str) -> int:
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        # parse and get each word from sentence
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        words = sentence.split()
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        # regular expression pattern for valid words
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        pattern = re.compile(r"^([a-z]+\-?[a-z]+[!\.,]?)$|^([a-z]*[!\.,]?)$")
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        # valid word count
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        count = 0
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        # scan each word from word pool
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        for word in words:
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            # judge whether current word is valid or not
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            match = re.match(pattern, word)
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            if match:
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                count += 1
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        return count