Graphql query flutter

String query = '''
      mutation CREATE_COMMENT(\$productId: String!, \$content: String!, \$rating: Float!, \$images: [String!]!){
          createComment(productId: \$productId, comment: {content: \$content , rating: \$rating, images: \$images }){
            content,
            rating,
            userId
          }
        }
    ''';