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wav2mid(https://github.com/jsleep/wav2mid)
preprocess.pyを実行しようとしているのですがTypeError: expected string or bufferというエラーを吐いてどうしても前に進めません
$ python preprocess.py
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site- 
packages/scipy/linalg/basic.py:17: RuntimeWarning: numpy.dtype size 
changed, may indicate binary incompatibility. Expected 96, got 88
  from ._solve_toeplitz import levinson
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/scipy/linalg/__init__.py:207: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from ._decomp_update import *
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/scipy/special/__init__.py:640: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from ._ufuncs import *
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/scipy/special/_ellip_harm.py:7: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from ._ellip_harm_2 import _ellipsoid, _ellipsoid_norm
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/scipy/interpolate/_bsplines.py:10: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from . import _bspl
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/scipy/sparse/lil.py:19: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from . import _csparsetools
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/scipy/sparse/csgraph/__init__.py:165: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from ._shortest_path import shortest_path, floyd_warshall, dijkstra,\
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/scipy/sparse/csgraph/_validation.py:5: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from ._tools import csgraph_to_dense, csgraph_from_dense,\
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/scipy/sparse/csgraph/__init__.py:167: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from ._traversal import breadth_first_order, depth_first_order, \
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/scipy/sparse/csgraph/__init__.py:169: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from ._min_spanning_tree import minimum_spanning_tree
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/scipy/sparse/csgraph/__init__.py:170: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from ._reordering import reverse_cuthill_mckee, maximum_bipartite_matching, \
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/scipy/spatial/__init__.py:95: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from .ckdtree import *
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/scipy/spatial/__init__.py:96: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from .qhull import *
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/scipy/spatial/_spherical_voronoi.py:18: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from . import _voronoi
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/scipy/spatial/distance.py:122: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from . import _hausdorff
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/scipy/ndimage/measurements.py:36: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from . import _ni_label
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/pandas/_libs/__init__.py:4: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from .tslib import iNaT, NaT, Timestamp, Timedelta, OutOfBoundsDatetime
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/pandas/__init__.py:26: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from pandas._libs import (hashtable as _hashtable,
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/pandas/core/dtypes/common.py:6: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from pandas._libs import algos, lib
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/pandas/core/util/hashing.py:7: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from pandas._libs import hashing, tslib
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/pandas/core/indexes/base.py:7: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from pandas._libs import (lib, index as libindex, tslib as libts,
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/pandas/tseries/offsets.py:21: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  import pandas._libs.tslibs.offsets as liboffsets
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/pandas/core/ops.py:16: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from pandas._libs import algos as libalgos, ops as libops
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/pandas/core/indexes/interval.py:32: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from pandas._libs.interval import (
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/pandas/core/internals.py:14: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from pandas._libs import internals as libinternals
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/pandas/core/sparse/array.py:33: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  import pandas._libs.sparse as splib
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/pandas/core/window.py:36: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  import pandas._libs.window as _window
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/pandas/core/groupby/groupby.py:68: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from pandas._libs import (lib, reduction,
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/pandas/core/reshape/reshape.py:30: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from pandas._libs import algos as _algos, reshape as _reshape
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/pandas/io/parsers.py:45: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  import pandas._libs.parsers as parsers
/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/pandas/io/pytables.py:50: RuntimeWarning: numpy.dtype size changed, may indicate binary incompatibility. Expected 96, got 88
  from pandas._libs import algos, lib, writers as libwriters
Traceback (most recent call last):
  File "preprocess.py", line 11, in <module>
    import librosa
  File "/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/librosa/__init__.py", line 12, in <module>
    from . import core
  File "/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/librosa/core/__init__.py", line 104, in <module>
    from .time_frequency import *  # pylint: disable=wildcard-import
  File "/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/librosa/core/time_frequency.py", line 10, in <module>
    from ..util.exceptions import ParameterError
  File "/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/librosa/util/__init__.py", line 67, in <module>
    from .utils import *  # pylint: disable=wildcard-import
  File "/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/librosa/util/utils.py", line 111, in <module>
    def valid_audio(y, mono=True):
  File "/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/librosa/cache.py", line 49, in wrapper
    if self.cachedir is not None and self.level >= level:
  File "/Users/nogaminofolder/.pyenv/versions/2.7.9/lib/python2.7/site-packages/joblib/memory.py", line 847, in cachedir
    DeprecationWarning, stacklevel=2)
TypeError: expected string or buffer
環境
python2.7.9
os：mac os high sierra10.13.4
numpy：1.15.0
pretty midi：多分最新
tensorflow:多分１.５
です。プログラミングも機械学習も初心者同然なのでどなたかご教授いただければ幸いです。