443. String Compression

class Solution:
    def compress(self, chars):
        """
        :type chars: List[str]
        :rtype: int
        """
        position = 1
        word_number = 1
        while position < len(chars):
            # print(chars)
            if chars[position] == chars[position - 1]:
                word_number += 1 
                chars.pop(position)
            else:
                if word_number == 1:
                    position += 1
                else:
                    for j in range(len(str(word_number))):
                        chars.insert(position, str(word_number)[j])
                        position += 1
                    word_number = 1
                    position += 1
            # print(chars)
            # print('position is ', position)
        if word_number == 1:
            pass
        else:
            # print(str(word_number))
            for j in range(len(str(word_number))):
                chars.insert(position, str(word_number)[len(str(word_number))- 1 - j])
        print(chars)
        return len(chars)
        
intance = Solution()
print(intance.compress(["a"]))