[Zope] tal expression

Hi will these be possible? <tal:b tal:define='dictionary python: {"value1": ["one", "two", "three"], "value2": "two", "value3": "three"}'> <tal:b tal:replace='python: dictionary["value1"][5] | "Value not available"' /> </tal:b> Obviously these is an incorrect tal expression (the replace one) but there are any way to create an expression like these and correct? Thank you!!!