code: function (start, len) {
        if ('number' === typeof start) {
          if (start < 0 || start >= _emberMetalProperty_get.get(this, 'length')) {
            throw new _emberMetalError.default(OUT_OF_RANGE_EXCEPTION);
          }
  
          // fast case
          if (len === undefined) {
            len = 1;
          }
  
          this.replace(start, len, EMPTY);
        }
  
        return this;
      }
docs: Remove an object at the specified index using the `replace()` primitive
  method. You can pass either a single index, or a start and a length.
  If you pass a start and length that is beyond the
  length this method will throw an `OUT_OF_RANGE_EXCEPTION`.
  ```javascript
  var colors = ['red', 'green', 'blue', 'yellow', 'orange'];
  colors.removeAt(0);     // ['green', 'blue', 'yellow', 'orange']
  colors.removeAt(2, 2);  // ['green', 'blue']
  colors.removeAt(4, 2);  // Error: Index out of range
  ```
  @method removeAt
  @param {Number} start index, start of range
  @param {Number} len length of passing range
  @return {Ember.Array} receiver
  @public