<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def type(self):
 """Certificate type. :return: The type of the certificate. :rtype: CertificateType """

        if self._device_mode == 1 or self._type == CertificateType.developer:
            return CertificateType.developer
        elif self._type == CertificateType.bootstrap:
            return CertificateType.bootstrap
        else:
            return CertificateType.lwm2m