def import_certificate(self, certificate):
        """
        Import a valid certificate. Certificate can be either a file path
        or a string of the certificate. If string certificate, it must include
        the -----BEGIN CERTIFICATE----- string.
        
        :param str certificate_file: fully qualified path to certificate file
        :raises CertificateImportError: failure to import cert with reason
        :raises IOError: file not found, permissions, etc.
        :return: None
        """
        multi_part = 'signed_certificate' if self.typeof == 'tls_server_credentials'\
            else 'certificate'
        self.make_request(
            CertificateImportError,
            method='create',
            resource='certificate_import',
            headers = {'content-type': 'multipart/form-data'}, 
            files={ 
                    multi_part: open(certificate, 'rb') if not \
                        pem_as_string(certificate) else certificate
                })