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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 _str_to_datetime(self, str_value):
 """Parses a `YYYY-MM-DD` string into a datetime object."""

        try:
            ldt = [int(f) for f in str_value.split('-')]
            dt = datetime.datetime(*ldt)
        except (ValueError, TypeError):
            return None
        return dt