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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 _parse(self, e):
 """Parses an exception, returns its message."""


        # MySQL
        matches = re.search(r"^\(_mysql_exceptions\.OperationalError\) \(\d+, \"(.+)\"\)$", str(e))
        if matches:
            return matches.group(1)

        # PostgreSQL
        matches = re.search(r"^\(psycopg2\.OperationalError\) (.+)$", str(e))
        if matches:
            return matches.group(1)

        # SQLite
        matches = re.search(r"^\(sqlite3\.OperationalError\) (.+)$", str(e))
        if matches:
            return matches.group(1)

        # Default
        return str(e)