Change Expression._simplified to a property
Change Expression._simplified to a property

pombredanne/pyeda,karissa/pyeda,pombredanne/pyeda,cjdrake/pyeda,sschnug/pyeda,pombredanne/pyeda,GtTmy/pyeda,GtTmy/pyeda,sschnug/pyeda,GtTmy/pyeda,cjdrake/pyeda,karissa/pyeda,karissa/pyeda,cjdrake/pyeda,sschnug/pyeda