'Given a query dict like
\'Steps.member.1.Name\': [\'example1\'],
\'Steps.member.1.ActionOnFailure\': [\'TERMINATE_JOB_FLOW\'],
\'Steps.member.1.HadoopJarStep.Jar\': [\'streaming1.jar\'],
\'Steps.member.2.Name\': [\'example2\'],
\'Steps.member.2.ActionOnFailure\': [\'TERMINATE_JOB_FLOW\'],
\'Steps.member.2.HadoopJarStep.Jar\': [\'streaming2.jar\'],
returns
\'name\': u\'example1\',
\'action_on_failure\': u\'TERMINATE_JOB_FLOW\',
\'hadoop_jar_step._jar\': u\'streaming1.jar\',
\'name\': u\'example2\',
\'action_on_failure\': u\'TERMINATE_JOB_FLOW\',
\'hadoop_jar_step._jar\': u\'streaming2.jar\','

def _get_list_prefix(self, param_prefix):

    results = []
    param_index = 1
    while True:
        index_prefix = u'{0}.{1}.'.format(param_prefix, param_index)
        new_items = {}
        for (key, value) in self.querystring.items():
            if key.startswith(index_prefix):
                new_items[camelcase_to_underscores(key.replace(index_prefix, u''))] = value[0]
        if (not new_items):
            break
        results.append(new_items)
        param_index += 1
    return results
