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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_configfile():
 """Return full path to configuration file. - Linux: ~/.local/share/pyfilemail - OSX: ~/Library/Application Support/pyfilemail - Windows: C:\\\Users\\\{username}\\\AppData\\\Local\\\pyfilemail :rtype: str """


    ad = appdirs.AppDirs('pyfilemail')
    configdir = ad.user_data_dir
    configfile = os.path.join(configdir, 'pyfilemail.cfg')

    return configfile