[WIP]Pad

[SoluMilken]

Please fix these error.

flake8
./strpipe/toolkit/test/test_pad_sentences.py:85:5: E124 closing bracket does not match visual indentation
./strpipe/toolkit/test/test_pad_sentences.py:97:5: E124 closing bracket does not match visual indentation
./strpipe/toolkit/test/test_pad_sentences.py:109:5: E124 closing bracket does not match visual indentation
./strpipe/toolkit/test/test_pad_sentences.py:121:5: E124 closing bracket does not match visual indentation
./strpipe/toolkit/test/test_pad_sentences.py:133:5: E124 closing bracket does not match visual indentation
./strpipe/toolkit/test/test_pad_sentences.py:142:5: E128 continuation line under-indented for visual indent
5     E124 closing bracket does not match visual indentation
1     E128 continuation line under-indented for visual indent
make: *** [lint] Error 1
The command "make lint" exited with 2.
0.72s$ make test
pytest
============================= test session starts ==============================
platform linux -- Python 3.6.3, pytest-3.3.0, py-1.5.2, pluggy-0.6.0
rootdir: /home/travis/build/Yoctol/strpipe, inifile:
plugins: mock-1.10.0
collected 47 items / 1 errors                                                  
==================================== ERRORS ====================================
________________ ERROR collecting strpipe/ops/tests/test_pad.py ________________
strpipe/ops/tests/test_pad.py:80: in <module>
    Pad(sos_token='<START_TOK>'),
strpipe/ops/pad.pyx:28: in strpipe.ops.pad.Pad.__init__
    cdef int _maxlen
E   TypeError: __init__() got an unexpected keyword argument 'sos_token'
!!!!!!!!!!!!!!!!!!! Interrupted: 1 errors during collection !!!!!!!!!!!!!!!!!!!!
=========================== 1 error in 0.29 seconds ============================

[absolutelyNoWarranty]

@stegben Regression test 要怎麼處理？

[stegben]

wait, why closed?