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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def find(self, title):
 """Return the first worksheet with the given title. Args: title(str):
 title/name of the worksheet to return Returns: WorkSheet: contained worksheet object Raises: KeyError: if the spreadsheet has no no worksheet with the given ``title`` """

        if title not in self._titles:
            raise KeyError(title)
        return self._titles[title][0]