anyone blocked in pip install libmr

[ZhenLiuBuaa]

i create a new virtual env using anaconda, and i get a error when pip install libmr and cant solve it.
the log is:
Collecting libmr
Cache entry deserialization failed, entry ignored
Using cached https://files.pythonhosted.org/packages/f3/48/f9d43abb742cbebec15933a052042da84d682da2142e803a0c1fa4524210/libmr-0.1.9.zip
Complete output from command python setup.py egg_info:
Traceback (most recent call last):
File "", line 1, in
File "/tmp/pip-build-ht5g3565/libmr/setup.py", line 17, in
language="c++",
File "/home/lz/.conda/envs/polar_sar/lib/python3.6/site-packages/Cython/Build/Dependencies.py", line 579, in cythonize
aliases=aliases)
File "/home/lz/.conda/envs/polar_sar/lib/python3.6/site-packages/Cython/Build/Dependencies.py", line 503, in create_extension_list
explicit_modules = set([m.name for m in patterns if isinstance(m, Extension)])
TypeError: 'Extension' object is not iterable

----------------------------------------

Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-ht5g3565/libmr/

if anyone has useful advice, thanks very much