python之为什么意外缩进

为什么会这样？

def LoadPackageList(): 
    try: 
        #Attempts to load package list... Adds each neccessary attribute into array 
        print("Loading Package List... please wait") 
        packages = [] 
        packagelisturl = os.getcwd() + "packages.list" 
        dom = minidom.parse(urllib.urlopen(packagelisturl)) 
        try: 
            for eachattributeofpkglist in dom.GetElementsByTagNameNS(packagelist, 'packages'): 
                packages.append({ 
                    'title': node.getAttribute('title'), 
                    'shortname': node.getAttribute('shortname'), 
                    'dlurl': node.getAttributes('dlurl'), 
                    'description': node.getAttributes('description'), 
                    'tags': node.getAttributes('tags'), 
                    'infopage': node.getAttributes('infopage'), 
                    'quality': node.getAttributes('quality'), 
                    'id': node.getAttributes('id') 
            }) 
 
        except LoadPackageListFailed: 
            print("Loading Package List failed... try again soon or manually update this release!") 
            Write2ErrorLog(LoadPackageListFailed) 
#Indent Here Fails             
def Usage(): 
#prints usage and closes 
    print ("Invalid Argument Specified, please retry using the format stated below\n") 
    print ("*** Simtho Usage Parameters ***\n") 
    print ("-i Installs Local App, include full path") 
    print ("-u Uninstalls Installed App,include ID or Name") 
    print ("-l Lists all installed Apps and their ID") 
    print ("-a Lists All Apps in Repository") 
    print ("-s Downloads and Installs App from repository, enter the title or id number") 
    print ("-w Downloads and Installs Single App from a full link") 
    print ("-r Removes All Packages installed\n") 
    print ("*** End of Simtho Usage ***") 
    os._exit(1) 
    return; 

请您参考如下方法:

尝试通过 python -t 运行它，看看其中某处是否混合了制表符和空格。

作为旁注:使用 optparse处理命令行参数。它将使您的生活更轻松，并产生一个漂亮的一致界面。