@staticmethod
def _filter(ftype):
    """
        Internal function to generate text string for setting up default files.
        """
    if ftype == '*':
        return 'AllFiles (*)'
    if ftype == 'dicom':
        return 'Dicom Files (*.dcm, *.ima)'
    if ftype == 'ctx':
        return 'CtxCube Files (*.ctx)'
    if ftype == 'hed':
        return 'Header Files (*.hed)'
    if ftype == 'dos':
        return 'DosCube Files (*.dos)'
    if ftype == 'let':
        return 'LETCube Files (*.dosemlet.dos)'
    return 'AllFiles (*)'
