Internal Error

invalid command name ""
    while executing
"$sidebar css set {*}{
  float right
  width 200px
  overflow-y auto
  height 600px
}"
    ("eval" body line 11)
    invoked from within
"eval {*}$args"
    (class "::clay::yggdrasil" method "eval" line 2)
    invoked from within
"my  eval [dict get $data body]"
    (class "::httpd::content.cuneiform" method "content" line 15)
    invoked from within
"my content"