Adding some Casbah object methods to Scala Maps

PimpMyMap.scala

implicit def pimpMyMap(underlying: Map[_,_]) = new { 

  /** Lazy utility method to allow typing without conflicting with Map's required get() method and causing ambiguity */
  def getAs[A <: Any : Manifest](key: Any): Option[A] = {
    require(manifest[A] != manifest[scala.Nothing], 
            "Type inference failed; getAs[A]() requires an explicit type argument " +
            "(e.g. mapObject.getAs[<ReturnType>](somegetAKey) ) to function correctly.")

    underlying.get(key) match {
      case null => None 
      case value => Some(value.asInstanceOf[A])
    }
  }

     /** 
   * as
   *
   * Works like apply(), unsafe, bare return of a value.
   * Returns default if nothing matching is found, else
   * tries to cast a value to the specified type.
   * 
   * Unless you overrode it, default throws
   * a NoSuchElementException
   * 
   * @param  key (String) 
   * @tparam A 
   * @return (A)
   * @throws NoSuchElementException
   */
  def as[A <: Any : Manifest](key: Any) = {
    require(manifest[A] != manifest[scala.Nothing], 
            "Type inference failed; as[A]() requires an explicit type argument" + 
            "(e.g. mapObject.as[<ReturnType>](someKey) ) to function correctly.")

    underlying.get(key) match {
      case null => default(key)
      case value => value.asInstanceOf[A]
    }
  }

}