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_1 = [ 0 ]
      for var_2 in range ( var_0 ) :
          for var_3 in reversed ( range ( len ( var_1 ) ) ) :
              var_1.append ( var_1 [ var_3 ] + ( 1 << var_2 ) )
      return var_1
  