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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 open(cls, title, conn=None, google_user=None, google_password=None):
 """ Open the spreadsheet named ``title``. If no spreadsheet with that name exists, a new one will be created. """

        spreadsheet = cls.by_title(title, conn=conn, google_user=google_user,
                                   google_password=google_password)
        if spreadsheet is None:
            spreadsheet = cls.create(title, conn=conn, google_user=google_user,
                                     google_password=google_password)
        return spreadsheet