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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 GetFilename(multiple=False, sep='|', **kwargs):
 """Prompt the user for a filename. This will raise a Zenity File Selection Dialog. It will return a list with the selected files or None if the user hit cancel. multiple - True to allow the user to select multiple files. sep - Token to use as the path separator when parsing Zenity's return string. kwargs - Optional command line parameters for Zenity such as height, width, etc."""


    args = []
    if multiple:
        args.append('--multiple')
    if sep != '|':
        args.append('--separator=%s' % sep)
    
    for generic_args in kwargs_helper(kwargs):
        args.append('--%s=%s' % generic_args)

    p = run_zenity('--file-selection', *args)

    if p.wait() == 0:
        return p.stdout.read()[:-1].split('|')