<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_file_extension(filepath):
 """ Copy if anyconfig.utils.get_file_extension is not available. '' 'txt' 'xz' """

    _ext = os.path.splitext(filepath)[-1]
    if _ext:
        return _ext[1:] if _ext.startswith('.') else _ext

    return ''