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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 fmt_sia(sia, ces=True):
 """Format a |SystemIrreducibilityAnalysis|."""

    if ces:
        body = (
            '{ces}'
            '{partitioned_ces}'.format(
                ces=fmt_ces(
                    sia.ces,
                    'Cause-effect structure'),
                partitioned_ces=fmt_ces(
                    sia.partitioned_ces,
                    'Partitioned cause-effect structure')))
        center_header = True
    else:
        body = ''
        center_header = False

    title = 'System irreducibility analysis: {BIG_PHI} = {phi}'.format(
        BIG_PHI=BIG_PHI, phi=fmt_number(sia.phi))

    body = header(str(sia.subsystem), body, center=center_header)
    body = header(str(sia.cut), body, center=center_header)
    return box(header(title, body, center=center_header))