类型不匹配;发现：play.api.libs.iteratee.Enumerator [reactivemongo.bson.BSONDocument] required：Boolean

Question

package repos

import javax.inject.Inject

import play.api.libs.json.{JsObject, Json}
import play.modules.reactivemongo.{ReactiveMongoApi, ReactiveMongoComponents,ReactiveMongoPlugin}
import play.modules.reactivemongo.json._
import play.modules.reactivemongo.json.collection.JSONCollection
import reactivemongo.api.{QueryOpts, ReadPreference}
import reactivemongo.api.commands.WriteResult
import reactivemongo.bson.{BSONDocument, BSONObjectID}
import reactivemongo.bson._
import reactivemongo.api.collections.bson.BSONCollection
import scala.language.existentials
import scala.concurrent.{ExecutionContext, Future}
import scala.util.{Try, Success, Failure}
import models._
import play.api.Logger
import play.api.libs.iteratee.Enumerator
trait MongoDao[T] extends DaoHelper{
  val collectionName: String
  import play.api.Play.current
  lazy val reactiveMongoApi = current.injector.instanceOf[ReactiveMongoApi]
  def collection = reactiveMongoApi.db.collection[BSONCollection](collectionName)

  /**
    * Inserts a list of T into mongo
    *
    * @param docList - List of T
    * @param writer - The BSONDocumentWriter on the companion object for T
    * @return - a Future[Try[Int]]
    */
  def insert(docList: List[T])(implicit writer: BSONDocumentWriter[T]): Future[Try[Int]] = {
    Logger.debug(s"Inserting document: [collection=$collectionName, data=$docList]")
    val enumerator = Enumerator.enumerate(docList.map( t => writer.write(t)))
    collection.bulkInsert(enumerator).map{ Success(_)}
  }

}

任何人都知道问题来自哪里？