Python使用模块Pyserial模块报<ImportError:No module named tools.list_ports>

用pip安装pyserial后:sudo -H pip install pyserial，运行新建的程序，名称为serial.py，程序中用到:import serial.toos.list_ports,但总是提示ImportError:No module named tools.list_ports，在度娘一顿乱搜后，在stack overflow<http://stackoverflow.com/questions/14108428/pyserial-no-module-named-tools>看到有人问这个问题，一个个回答看过来，当看到：

I got here because I had the same problem. The strange thing was that

import serial

worked, but

from serial.tools import list_ports

didn't.

Turns out stupid me named the script "serial.py". After renaming it everything worked.
当时是五味杂陈，一时犯贱工程命名也是serial.py，当再重新命名为MySerial.py后，python MySerial.py编译时:
File "MySerial.py", line 15, in <module>

import serial
File "/User/zhang/Desktop/python/serial_uart/serial.py", line 18, in <module>

ImportError: No module named tools.list_ports

此时已经没有serial.py文件了，怎么报的错误还和serial.py扯上关系，最后发现该文件夹下生成了一个serial.pyc的文件，删除之后运行正常，都是名字惹的祸。