使用sbt程序集构建Scala代码,失败

下面是我的build.sbt文件：

import AssemblyKeys._

name := "Simple Project"
version := "1.0"
organization := "com.myorg"
scalaVersion := "2.11.4"
libraryDependencies ++= Seq(
  // Spark dependency
  "org.apache.spark" % "spark-core_2.10" % "1.2.0" % "provided",// Third party libraries
  "net.sf.jopt-simple" % "jopt-simple" % "4.3","joda-time" % "joda-time" % "2.0"
)
libraryDependencies += Defaults.sbtPluginExtra("com.eed3si9n" % "sbt-assembly" % "0.7.2","0.11.2","2.9.1")
// This statement includes the assembly plugin capabilities
assemblySettings
// Configure jar named used with the assembly plug-in
jarName in assembly := "my-project-assembly.jar"
// A special option to exclude Scala itself form our assembly jar,since Spark
// already bundles Scala.
assemblyOption in assembly := (assemblyOption in assembly).value.copy(includeScala = false)

我面临的错误是：

build.sbt:16: error: type mismatch;
 found   : Seq[sbt.Project.Setting[_]]
 required: sbt.internals.DslEntry
assemblySettings
^
[error] Type error in expression
Project loading failed: (r)etry,(q)uit,(l)ast,or (i)gnore?