docs: function(properties, value, equals, out)
    {
      var where = createWhere( properties, value, equals );
      var changes = out && out instanceof ModelCollection ? out : this.cloneEmpty();
  
      this.each(function(model)
      {
        if ( where( model ) && model.$hasChanges() )
        {
          changes.put( model.$key(), model.$getChanges() );
        }
      });
  
      return changes;
    }