code: def _operation(self, ndim, ds, outs, ks, ss, ps, dilate):
      c0 = self._compile_c0(outs, ks)
      kx, kxs = self._compile_kx(ndim, outs, ks)
      out_x, out_xs = self._compile_out_x(ndim, outs)
      main = self._compile_main(
          ndim, ds, ks, ss, ps, dilate, kxs, out_xs
      )
      return "\n".join(c0 + kx + out_x + main)
  
imports: import functools
  import six
  from chainer.backends import cuda
label_desc: Use image node_id 7 for calling the Im2colNDKernel obj's underlying member method code with example usage: obj._operation(ndim, ds, outs, ks, ss, ps, dilate) and returns: str