code: def merge_instances(cls, inst1, inst2):
          
          return Instances(javabridge.static_call(
              "weka/core/Instances", "mergeInstances",
              "(Lweka/core/Instances;Lweka/core/Instances;)Lweka/core/Instances;", inst1.jobject, inst2.jobject))
docs: Merges the two datasets (side-by-side).
  
          :param inst1: the first dataset
          :type inst1: Instances or str
          :param inst2: the first dataset
          :type inst2: Instances
          :return: the combined dataset
          :rtype: Instances