python遇到动态函数---TypeError: unbound method a() must be called with A instance as first argument (got nothing instead)

TypeError: unbound method a() must be called with A instance as first argument (got nothing instead)

# encoding: utf-8

import time
import threading

class test:

    def follow(self,thefile):
        thefile.seek(0,2)
        while True:
            line = thefile.readline()
            if not line:
                time.sleep(0.1)
                continue
                yield line

if __name__ == '__main__':

    # obj = test()
    file1 = 'log.txt'
    file2 = 'result.txt'
    logfile = open(file2,"r")
    # loglines = obj.follow(logfile)
    loglines = test.follow(logfile)
    for line in loglines:
        print line,

运行结果

C:Python27python.exe C:/Users/sys_syspifarm/.ssh/MagicBox/source/test.py
Traceback (most recent call last):
File "C:/Users/sys_syspifarm/.ssh/MagicBox/source/test.py", line 44, in <module>
loglines = test.follow(logfile)
TypeError: unbound method follow() must be called with test instance as first argument (got file instance instead)

Process finished with exit code 1

错误原因：函数a()非静态方法，故需实例化然后才能使用，改正如下：

# encoding: utf-8

import time
import threading

class test:

    def follow(self,thefile):
        thefile.seek(0,2)
        while True:
            line = thefile.readline()
            if not line:
                time.sleep(0.1)
                continue
                yield line

if __name__ == '__main__':

    obj = test()
    file1 = 'log.txt'
    file2 = 'result.txt'
    logfile = open(file2,"r")
    loglines = obj.follow(logfile)
    # loglines = test.follow(logfile)
    for line in loglines:
        print line,

obj = test()需要把方法实例化一下