Ask for multiple filenames and return the open file
    objects

    returns a list of open file objects or an empty list if
    cancel selected

def askopenfiles(mode="r", **options):
    """Ask for multiple filenames and return the open file
    objects

    returns a list of open file objects or an empty list if
    cancel selected
    """

    files = askopenfilenames(**options)
    if files:
        ofiles = []
        for filename in files:
            ofiles.append(open(filename, mode))
        files = ofiles
    return files