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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_valid_cidr(string_network):
 """ Very simple check of the cidr format in no_proxy variable. :rtype: bool """

    if string_network.count('/') == 1:
        try:
            mask = int(string_network.split('/')[1])
        except ValueError:
            return False

        if mask < 1 or mask > 32:
            return False

        try:
            socket.inet_aton(string_network.split('/')[0])
        except socket.error:
            return False
    else:
        return False
    return True