How to use the css-tree.fromPlainObject function in css-tree

Object.keys(cleaned).forEach(url => {
    // console.log('For URL', url);
    const obj = cleaned[url]
    const cleanedAst = csstree.fromPlainObject(obj)
    const cleanedCSS = csstree.translate(cleanedAst)
    console.log(cleanedCSS)
  })

const allCleanedCSS = cleanedCSS.map((ast) => {
            const cleanedAst = fromPlainObject(ast);
            return generate(cleanedAst)
        }).join('\n');
        const finalCss = collectImportantComments(allCleanedCSS);

const cleanedStyles = styleSheets.map(ast => {
      const cleanedAST = fromPlainObject(cleaner(ast, checker))
      return generate(cleanedAST)
    })
    const finalCSS = collectImportantComments(cleanedStyles.join('\n'))

const allCleanedCSS = cleanedCSS.map((ast) => {
      const cleanedAst = fromPlainObject(ast)
      return generate(cleanedAst)
    }).join('\n')