use __contains__, index or split instead of str.find str.find return -1 when the substring is not found, -1 evaluate to True and is a valid index, which can lead to bugs. Using alternatives when possible makes the code clearer and less prone to bugs. (and __contains__ is faster in microbenchmarks)

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    <title>#desc|strip|firstline|strip|escape#</title>
    <link>#url#?f=#filenode|short#;file=#file|urlescape#</link>
    <description><![CDATA[#desc|strip|escape|addbreaks#]]></description>
    <author>#author|obfuscate#</author>
    <pubDate>#date|rfc822date#</pubDate>>
</item>