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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 list():
 """ List available format. """

    choice_len = max(map(len, _input_choices.keys()))
    tmpl = "  {:<%d}: {}\n" % choice_len
    text = ''.join(map(
        lambda k_v: tmpl.format(k_v[0], k_v[1][0]), six.iteritems(_input_choices)))
    click.echo(text)