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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 is_intf_up(intf):
 """Function to check if a interface is up. """

    intf_path = '/'.join(('/sys/class/net', intf))
    intf_exist = os.path.exists(intf_path)
    if not intf_exist:
        LOG.error("Unable to get interface %(intf)s, Interface dir "
                  "%(dir)s does not exist",
                  {'intf': intf, 'dir': intf_path})
        return False
    try:
        oper_file = '/'.join((intf_path, 'operstate'))
        with open(oper_file, 'r') as fd:
            oper_state = fd.read().strip('\n')
            if oper_state == 'up':
                return True
    except Exception as e:
        LOG.error("Exception in reading %s", str(e))
    return False