BUG: improve the interface of `tofile` method; import os
BUG: improve the interface of `tofile` method; import os

charris/numpy,jakirkham/numpy,seberg/numpy,anntzer/numpy,endolith/numpy,numpy/numpy,rgommers/numpy,pbrod/numpy,pdebuyl/numpy,anntzer/numpy,pdebuyl/numpy,mattip/numpy,mhvk/numpy,numpy/numpy,seberg/numpy,rgommers/numpy,seberg/numpy,numpy/numpy,charris/numpy,pdebuyl/numpy,jakirkham/numpy,simongibbons/numpy,endolith/numpy,mhvk/numpy,pbrod/numpy,mattip/numpy,numpy/numpy,mattip/numpy,jakirkham/numpy,jakirkham/numpy,anntzer/numpy,simongibbons/numpy,mhvk/numpy,charris/numpy,rgommers/numpy,endolith/numpy,charris/numpy,pbrod/numpy,jakirkham/numpy,anntzer/numpy,pbrod/numpy,simongibbons/numpy,pbrod/numpy,seberg/numpy,mhvk/numpy,mattip/numpy,simongibbons/numpy,rgommers/numpy,endolith/numpy,simongibbons/numpy,pdebuyl/numpy,mhvk/numpy