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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 clouds(clds: [Cloud], unit: str = 'ft') -> str: # type: ignore """ Format cloud list into a readable sentence Returns the translation string Ex: Broken layer at 2200ft (Cumulonimbus), Overcast layer at 3600ft - Reported AGL """

    if clds is None:
        return ''
    ret = []
    for cloud in clds:
        if cloud.altitude is None:
            continue
        cloud_str = CLOUD_TRANSLATIONS[cloud.type]
        if cloud.modifier:
            cloud_str += f' ({CLOUD_TRANSLATIONS[cloud.modifier]})'
        ret.append(cloud_str.format(cloud.altitude * 100, unit))
    if ret:
        return ', '.join(ret) + ' - Reported AGL'
    return 'Sky clear'