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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 get_conn(cls):
 """Return a connection object to the ldap database"""

        conn = cls._conn
        if conn is None or conn.closed:
            conn = ldap3.Connection(
                settings.CAS_LDAP_SERVER,
                settings.CAS_LDAP_USER,
                settings.CAS_LDAP_PASSWORD,
                client_strategy="RESTARTABLE",
                auto_bind=True
            )
            cls._conn = conn
        return conn