ruby-on-rails - haml 语法错误，意外的keyword_ensure，期待$end

Question

已搜索广泛但没有找到适用的答案：

.activity
    - form_tag("/contacts/mightyfield_action", :method => "post",:class=>['form', 'form-add'])
        = text_field_tag(:name => "content", :rows => "6", :placeholder => "Notiz oder Aufgabe hinzufügen")
        .actions
            .help Hier steht vielleicht nützlicher Text
            .buttons.right
            = submit_tag("Send", :value => "Speichern", :class=>['btn', 'btn-primary'])

    %ul
        - @contact.actions.each do |action|
            %li
                .action-user
                    %img.avatar{ :src => "http://gravatar.com/avatar/#{@gravatar_id}?s=200", :width => "35px" }
                .action-content
                    = action.content
                    .action-meta= "von #{action.user.name} #{action.created_at}"


- content_for :sidebar do

    %h3 
        Aufgaben
        %span.small= "zu #{@contact.first_name} #{@contact.last_name}"

    .tasks
        %ul
        - @contact.tasks.each do |task|
            %li
                =check_box_tag(:pet_cat)
                =label_tag(:pet_cat, task.title)

错误语法错误，意外的keyword_ensure，期望$end不断弹出最后两行。我完全迷路了。