<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def parseFilename(filename):
 """ Parse out filename from any specified extensions. Returns rootname and string version of extension name. """


    # Parse out any extension specified in filename
    _indx = filename.find('[')
    if _indx > 0:
        # Read extension name provided
        _fname = filename[:_indx]
        _extn = filename[_indx + 1:-1]
    else:
        _fname = filename
        _extn = None

    return _fname, _extn