Fix issue #1054

[RyanTsang]

Fix issue #1054

Checks

• [x] My pull request adheres to the code style of this project
• [ ] My code requires changes to the documentation
• [ ] I have updated the documentation as required
• [x] All the tests have passed

Additional Information

no

test result:

root@5555f1d745b7:/usr/jasmin# coverage run --source=jasmin -m twisted.trial tests
tests.test_gsm_encoding
  TestEncodingFunctions
    test_decoding_supported_unicode_gsm ...                                [OK]
    test_encoding_supported_greek_unicode_gsm ...                          [OK]
    test_encoding_supported_quirk_unicode_gsm ...                          [OK]
    test_encoding_supported_unicode_gsm ...                                [OK]
    test_is_valid_gsm_false ...                                            [OK]
    test_is_valid_gsm_true ...                                             [OK]
tests.test_mms
  TestMmsDecoding
    test_decoding_27d0a048cd79555de05283a22372b0eb_mms ...                 [OK]
    test_decoding_BTMMS_mms ...                                            [OK]
    test_decoding_SEC_SGHS300M ...                                         [OK]
    test_decoding_SIMPLE_mms ...                                           [OK]
    test_decoding_SonyEricssonT310_R201_mms ...                            [OK]
    test_decoding_TOMSLOT_mms ...                                          [OK]
    test_decoding_from_data ...                                            [OK]
    test_decoding_gallery2test_mms ...                                     [OK]
    test_decoding_iPhone_mms ...                                           [OK]
    test_decoding_images_are_cut_off_debug_mms ...                         [OK]
    test_decoding_m_mms ...                                                [OK]
    test_decoding_openwave_mms ...                                         [OK]
    test_decoding_projekt_exempel_mms ...                                  [OK]
    test_encoding_m_sendnotifyresp_ind ...                                 [OK]
tests.test_sms
  TestEncodingFunctions
    test_converting_datetime_to_validity ...                               [OK]
    test_converting_timedelta_to_validity ...                              [OK]
  TestSmsDeliver
    test_decode_sms_confirmation ...                                       [OK]
    test_decode_weird_multipart_german_pdu ...                             [OK]
    test_decoding_7bit_pdu ...                                             [OK]
    test_decoding_7bit_pdu_data ...                                        [OK]
    test_decoding_datetime_gmtminusthree ...                               [OK]
    test_decoding_datetime_gmtplusone ...                                  [OK]
    test_decoding_delivery_status_report ...                               [OK]
    test_decoding_delivery_status_report_without_smsc_address ...          [OK]
    test_decoding_number_alphanumeric ...                                  [OK]
    test_decoding_odd_length_pdu_no_strict ...                             [OK]
    test_decoding_odd_length_pdu_strict_raises_valueerror ...              [OK]
    test_decoding_ucs2_pdu ...                                             [OK]
  TestSmsSubmit
    test_encoding_8bit_message ...                                         [OK]
    test_encoding_bad_csca_raises_error ...                                [OK]
    test_encoding_bad_number_raises_error ...                              [OK]
    test_encoding_class ...                                                [OK]
    test_encoding_csca ...                                                 [OK]
    test_encoding_message_with_latin1_chars ...                            [OK]
    test_encoding_multipart_7bit ...                                       [OK]
    test_encoding_multipart_7bit_egsm ...                                  [OK]
    test_encoding_request_status ...                                       [OK]
    test_encoding_ucs2_message ...                                         [OK]
    test_encoding_validity ...                                             [OK]
  TestSubmitPduCounts
    test_egsm_1 ...                                                        [OK]
    test_egsm_2 ...                                                        [OK]
    test_egsm_3 ...                                                        [OK]
    test_egsm_4 ...                                                        [OK]
    test_egsm_5 ...                                                        [OK]
    test_gsm_1 ...                                                         [OK]
    test_gsm_2 ...                                                         [OK]
    test_gsm_3 ...                                                         [OK]
    test_gsm_4 ...                                                         [OK]
    test_gsm_5 ...                                                         [OK]
    test_gsm_6 ...                                                         [OK]
    test_unicode_1 ...                                                     [OK]
    test_unicode_2 ...                                                     [OK]
    test_unicode_3 ...                                                     [OK]
    test_unicode_4 ...                                                     [OK]
    test_unicode_5 ...                                                     [OK]
    test_unicode_6 ...                                                     [OK]
tests.test_udh
  TestUserDataHeader
    test_user_data_header ...                                              [OK]
tests.test_wap
  TestSmsWapPush
    test_decoding_generic_wap_push ...                                     [OK]
    test_decoding_m_notification_ind ...                                   [OK]
    test_is_a_wap_push_notification ...                                    [OK]

-------------------------------------------------------------------------------
Ran 66 tests in 1.392s

PASSED (successes=66)