# File lib/methods.rb, line 955
def validate_ip_netmask(netmask, options=nil)
    known_args = [:Integer, :Version]
    is_integer = false
    version = 4

    # validate options
    if (options)
        raise ArgumentError, "Hash expected for argument 'options' but #{options.class} provided." if (!options.kind_of?(Hash))
        NetAddr.validate_args(options.keys,known_args)

        if (options.has_key?(:Integer) && options[:Integer] == true)
            is_integer = true
        end

        if (options.has_key?(:Version))
            version = options[:Version]
            if (version != 4 && version != 6)
                raise ArgumentError, ":Version should be 4 or 6, but was '#{version}'."
            end
        end
    end

    # validate netmask
    if (netmask.kind_of?(String))
        validate_netmask_str(netmask,version)
    elsif (netmask.kind_of?(Integer) )
        validate_netmask_int(netmask,version,is_integer)
    else
        raise ArgumentError, "Integer or String expected for argument 'netmask' but " +
                             "#{netmask.class} provided." if (!netmask.kind_of?(String) && !netmask.kind_of?(Integer))
    end

    return(true)
end