old_contents: from ncrelu import ncrelu
  from dgmm import dgmm
  from cdgmm import cdgmm
  from im2col import im2col, col2im
  from conv2d_depthwise import conv2d_depthwise
  
new_contents: from .ncrelu import ncrelu
  from .dgmm import dgmm
  from .cdgmm import cdgmm
  from .im2col import im2col, col2im
  from .conv2d_depthwise import conv2d_depthwise
  
subject: fix init for py3