【Pythonでimport matplotlib.pyplot】を使う際のエラー

## エラー
### Pythonでimport matplotlib.pyplot as pltしたら下記のエラーが出た

```
2019-06-01 23:41:58.053 python[65992:1275150] -[NSApplication _setup:]: unrecognized selector sent to instance 0x7fcd2f8ea010
2019-06-01 23:41:58.056 python[65992:1275150] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSApplication _setup:]: unrecognized selector sent to instance 0x7fcd2f8ea010'
*** First throw call stack:
(
        0   CoreFoundation                      0x00007fff390b3cf9 __exceptionPreprocess + 256
        1   libobjc.A.dylib                     0x00007fff63c48a17 objc_exception_throw + 48
        2   CoreFoundation                      0x00007fff3912db06 -[NSObject(NSObject) __retain_OA] + 0
        3   CoreFoundation                      0x00007fff390560ef ___forwarding___ + 1485
        4   CoreFoundation                      0x00007fff39055a98 _CF_forwarding_prep_0 + 120
        5   libtk8.6.dylib                      0x000000010ccf731d TkpInit + 413
        6   libtk8.6.dylib                      0x000000010cc4f17e Initialize + 2622
        7   _tkinter.cpython-36m-darwin.so      0x0000000109bf3a16 _tkinter_create + 1174
        8   python                              0x00000001014ca6c8 _PyCFunction_FastCallDict + 200
        9   python                              0x00000001015a184f call_function + 143
        10  python                              0x000000010159f54a _PyEval_EvalFrameDefault + 47098
        11  python                              0x0000000101592b89 _PyEval_EvalCodeWithName + 425
        12  python                              0x00000001015a2425 _PyFunction_FastCallDict + 373
        13  python                              0x00000001014493d0 _PyObject_FastCallDict + 320
        14  python                              0x0000000101470848 method_call + 136
        15  python                              0x0000000101450a2e PyObject_Call + 62
        16  python                              0x00000001014f1a35 slot_tp_init + 117
        17  python                              0x00000001014f5f81 type_call + 241
        18  python                              0x0000000101449341 _PyObject_FastCallDict + 177
        19  python                              0x0000000101451597 _PyObject_FastCallKeywords + 327
        20  python                              0x00000001015a1948 call_function + 392
        21  python                              0x000000010159f5fa _PyEval_EvalFrameDefault + 47274
        22  python                              0x00000001015a1c0c fast_function + 188
        23  python                              0x00000001015a18ac call_function + 236
        24  python                              0x000000010159f54a _PyEval_EvalFrameDefault + 47098
        25  python                              0x0000000101592b89 _PyEval_EvalCodeWithName + 425
        26  python                              0x00000001015a2425 _PyFunction_FastCallDict + 373
        27  python                              0x00000001014493d0 _PyObject_FastCallDict + 320
        28  python                              0x0000000101470848 method_call + 136
        29  python                              0x0000000101450a2e PyObject_Call + 62
        30  python                              0x000000010159f740 _PyEval_EvalFrameDefault + 47600
        31  python                              0x0000000101592b89 _PyEval_EvalCodeWithName + 425
        32  python                              0x00000001015a1cba fast_function + 362
        33  python                              0x00000001015a18ac call_function + 236
        34  python                              0x000000010159f54a _PyEval_EvalFrameDefault + 47098
        35  python                              0x00000001015a1c0c fast_function + 188
        36  python                              0x00000001015a18ac call_function + 236
        37  python                              0x000000010159f54a _PyEval_EvalFrameDefault + 47098
        38  python                              0x0000000101592b89 _PyEval_EvalCodeWithName + 425
        39  python                              0x00000001015a1cba fast_function + 362
        40  python                              0x00000001015a18ac call_function + 236
        41  python                              0x000000010159f54a _PyEval_EvalFrameDefault + 47098
        42  python                              0x0000000101592b89 _PyEval_EvalCodeWithName + 425
        43  python                              0x00000001015a1cba fast_function + 362
        44  python                              0x00000001015a18ac call_function + 236
        45  python                              0x000000010159f54a _PyEval_EvalFrameDefault + 47098
        46  python                              0x0000000101592b89 _PyEval_EvalCodeWithName + 425
        47  python                              0x00000001015eb0dc PyRun_FileExFlags + 252
        48  python                              0x00000001015ea83e PyRun_SimpleFileExFlags + 366
        49  python                              0x0000000101611156 Py_Main + 3734
        50  python                              0x0000000101441469 main + 313
        51  libdyld.dylib                       0x00007fff654763d5 start + 1
        52  ???                                 0x0000000000000002 0x0 + 2
)
libc++abi.dylib: terminating with uncaught exception of type NSException
Abort trap: 6
```

## 解決法
### importする前に下記のように２行追加するとエラーが消えた。
```
import matplotlib
matplotlib.use('TkAgg')
```
## 参照
https://github.com/MTG/sms-tools/issues/33