「Rails」Haml記載時のフォームへルパーに対してのclass名の指定ができません。ご教示お願いします。

Hamlファイルにclass名の指定をしたいのですが、どうしてもエラー文が表示されてしまいます。コードは下記に記載しています。今回の場合、いろんな場合を試してみました。クラス名の記述方法に関しては、下記の記事を参考にさせていただきました。
リンク内容
fieldクラスの、form.labelと、form.date_selectにクラス名を追加したい状態です。この二つのタグはそれぞれ違う記述法で試していますが、どちらのやり方もうまく行きません。この記述に対するエラー文がhamlファイルのしたにコードを挿入しておきます。また、エラー文の画像も挿入しておきました。確認お願いします。
リンク内容

_form.html.haml

= form_with(model: article, local: true) do |form|
  - if article.errors.any?
    #error_explanation
      %h2
        = pluralize(article.errors.count, "error")
        prohibited this article from being saved:
      %ul
        - article.errors.full_messages.each do |message|
          %li= message
  .field
    = form.label{ :post_date, :class => 'f' }
    = form.date_select :post_date{ :class 'a' }
  .field
    = form.label :title
    = form.text_field :title
  .field
    = form.label :content
    = form.text_area :content
  .actions
    = form.submit

ActionView::SyntaxErrorInTemplate in ArticlesController#new
Encountered a syntax error while rendering template: check = form_with(model: article, local: true) do |form| - if article.errors.any? #error_explanation %h2 = pluralize(article.errors.count, "error") prohibited this article from being saved: %ul - article.errors.full_messages.each do |message| %li= message .field = form.label{ :post_date, :class => 'f' } = form.date_select :post_date{ :class 'a' } .field = form.label :title = form.text_field :title .field = form.label :content = form.text_area :content .actions = form.submit
Extracted source (around line #11):
9
10
11
12
13
14

          %li= message
  .field
    = form.label{ :post_date, :class => 'f' }
    = form.date_select :post_date{ :class 'a' }
  .field
    = form.label :title

また、エラーに対するターミナルの記述も載せておきます。

ActionView::SyntaxErrorInTemplate (Encountered a syntax error while rendering template: check = form_with(model: article, local: true) do |form|
  - if article.errors.any?
    #error_explanation
      %h2
        = pluralize(article.errors.count, "error")
        prohibited this article from being saved:
      %ul
        - article.errors.full_messages.each do |message|
          %li= message
  .field
    = form.label{ :post_date, :class => 'f' }
    = form.date_select :post_date{ :class 'a' }
  .field
    = form.label :title
    = form.text_field :title
  .field
    = form.label :content
    = form.text_area :content
  .actions
    = form.submit

):
1:    = form_with(model: article, local: true) do |form|
2:      - if article.errors.any?
3:        #error_explanation
4:          %h2
5:            = pluralize(article.errors.count, "error")
6:            prohibited this article from being saved:
7:          %ul
8:            - article.errors.full_messages.each do |message|
9:              %li= message
10:      .field
11:        = form.label{ :post_date, :class => 'f' }
12:        = form.date_select :post_date{ :class 'a' }
13:      .field
14:        = form.label :title
15:        = form.text_field :title
16:      .field
17:        = form.label :content
18:        = form.text_area :content
19:      .actions
20:        = form.submit

app/views/articles/_form.html.haml:11: syntax error, unexpected ',', expecting '}'
app/views/articles/_form.html.haml:11: syntax error, unexpected '}', expecting ')'
app/views/articles/_form.html.haml:12: syntax error, unexpected '{', expecting ')'
app/views/articles/_form.html.haml:12: syntax error, unexpected '}', expecting ')'
app/views/articles/_form.html.haml:21: syntax error, unexpected end, expecting ')'
app/views/articles/_form.html.haml:21: syntax error, unexpected ensure, expecting ')'
app/views/articles/_form.html.haml:21: syntax error, unexpected end, expecting ')'
app/views/articles/_form.html.haml:11: syntax error, unexpected ',', expecting '}'
app/views/articles/_form.html.haml:11: syntax error, unexpected '}', expecting ')'
app/views/articles/_form.html.haml:12: syntax error, unexpected '{', expecting ')'
app/views/articles/_form.html.haml:12: syntax error, unexpected '}', expecting ')'
app/views/articles/_form.html.haml:21: syntax error, unexpected end, expecting ')'
app/views/articles/_form.html.haml:21: syntax error, unexpected ensure, expecting ')'
app/views/articles/_form.html.haml:21: syntax error, unexpected end, expecting ')'
app/views/articles/_form.html.haml:11: syntax error, unexpected ',', expecting '}'
app/views/articles/_form.html.haml:11: syntax error, unexpected '}', expecting ')'
app/views/articles/_form.html.haml:12: syntax error, unexpected '{', expecting ')'
app/views/articles/_form.html.haml:12: syntax error, unexpected '}', expecting ')'
app/views/articles/_form.html.haml:21: syntax error, unexpected end, expecting ')'
app/views/articles/_form.html.haml:21: syntax error, unexpected ensure, expecting ')'
app/views/articles/_form.html.haml:21: syntax error, unexpected end, expecting ')'
app/views/articles/_form.html.haml:11: syntax error, unexpected ',', expecting '}'
app/views/articles/_form.html.haml:11: syntax error, unexpected '}', expecting ')'
app/views/articles/_form.html.haml:12: syntax error, unexpected '{', expecting ')'
app/views/articles/_form.html.haml:12: syntax error, unexpected '}', expecting ')'
app/views/articles/_form.html.haml:21: syntax error, unexpected end, expecting ')'
app/views/articles/_form.html.haml:21: syntax error, unexpected ensure, expecting ')'
app/views/articles/_form.html.haml:21: syntax error, unexpected end, expecting ')'
app/views/articles/new.html.haml:2

問題の確認と解決案があれば、どなたかご教授お願いします！