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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 _connect(self):
 """Establish connection to PostgreSQL Database."""

        if self._connParams:
            self._conn = psycopg2.connect(**self._connParams)
        else:
            self._conn = psycopg2.connect('')
        try:
            ver_str = self._conn.get_parameter_status('server_version')
        except AttributeError:
            ver_str = self.getParam('server_version')
        self._version = util.SoftwareVersion(ver_str)