ur"""
    (
        <key[^>]*>\s*      # opening tag <key>
            (firstname|    # keys to obfuscate
             lastname|
             hash|
             password|
             newpassword)
        \s*</key[^>]*>\s*  # closing tag </key>
        <value[^>]*>       # opening tag <value>
    )   
        [^<>]+             # obfuscated value
    (
        </value[^>]*>      # closing tag </value>
    )
"""