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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 interface_ip(iface):
    '''
    Return `iface` IPv4 addr or an error if `iface` does not exist
    '''
    iface_info, error = _get_iface_info(iface)

    if error is False:
        inet = iface_info.get(iface, {}).get('inet', None)
        return inet[0].get('address', '') if inet else ''
    else:
        return error