comefrom: <qiyuangong>089_Gray_Code_1.py
code: def grayCode( n):
      res = [0]
      for i in range(n):
          for j in reversed(range(len(res))):
              res.append(res[j] + (1 << i))
      return res
masked: def sample_funcname ( var_0 ) :
      var_2 = [ 0 ]
      for var_4 in range ( var_0 ) :
          for var_7 in reversed ( range ( len ( var_2 ) ) ) :
              var_2.append ( var_2 [ var_7 ] + ( 1 << var_4 ) )
      return var_2
  