+ * @since 4.1.0 Introduced the 'class_submit' argument.
+ * @since 4.2.0 Introduced 'submit_button' and 'submit_fields' arguments.
+ *
+ * @param array $args {
+ * Optional. Default arguments and form fields to override.
+ *
+ * @type array $fields {
+ * Default comment fields, filterable by default via the 'comment_form_default_fields' hook.
+ *
+ * @type string $author Comment author field HTML.
+ * @type string $email Comment author email field HTML.
+ * @type string $url Comment author URL field HTML.
+ * }
+ * @type string $comment_field The comment textarea field HTML.
+ * @type string $must_log_in HTML element for a 'must be logged in to comment' message.
+ * @type string $logged_in_as HTML element for a 'logged in as [user]' message.
+ * @type string $comment_notes_before HTML element for a message displayed before the comment form.
+ * Default 'Your email address will not be published.'.
+ * @type string $comment_notes_after HTML element for a message displayed after the comment form.
+ * Default 'You may use these HTML tags and attributes ...'.
+ * @type string $id_form The comment form element id attribute. Default 'commentform'.
+ * @type string $id_submit The comment submit element id attribute. Default 'submit'.
+ * @type string $class_submit The comment submit element class attribute. Default 'submit'.
+ * @type string $name_submit The comment submit element name attribute. Default 'submit'.
+ * @type string $title_reply The translatable 'reply' button label. Default 'Leave a Reply'.
+ * @type string $title_reply_to The translatable 'reply-to' button label. Default 'Leave a Reply to %s',
+ * where %s is the author of the comment being replied to.
+ * @type string $cancel_reply_link The translatable 'cancel reply' button label. Default 'Cancel reply'.
+ * @type string $label_submit The translatable 'submit' button label. Default 'Post a comment'.
+ * @type string $submit_button HTML format for the Submit button.
+ * Default: '<input name="%1$s" type="submit" id="%2$s" class="%3$s" value="%4$s" />'.
+ * @type string $submit_field HTML format for the markup surrounding the Submit button and comment hidden
+ * fields. Default: '<p class="form-submit">%1$s %2$s</a>', where %1$s is the
+ * submit button markup and %2$s is the comment hidden fields.
+ * @type string $format The comment form format. Default 'xhtml'. Accepts 'xhtml', 'html5'.
+ * }
+ * @param int|WP_Post $post_id Post ID or WP_Post object to generate the form for. Default current post.